Wireless communication apparatus, communication method, computer program, and wireless communication system

ABSTRACT

[Solution] Provided is a wireless communication apparatus including: a frame generation unit configured to generate a frame including a plurality of subframes; a transmission unit configured to transmit the generated frame to another communication apparatus; and a notification unit configured to notify of information regarding a plurality of lengths of a short transmission time interval, which is a transmission time interval shorter than one subframe period in the subframe.

TECHNICAL FIELD

The present disclosure relates to a wireless communication apparatus, acommunication method as computer program and a wireless communicationsystem.

BACKGROUND ART

In Long Term Evolution (LTE), a transmission time interval (TTI) is setto 1 ms to realize a high data rate. By shortening the TTI, a round triptime (RTT) necessary for retransmission control is shortened and asystem latency is reduced.

In a case in which the TTI is 1 ms, a time necessary for a terminalapparatus to decode data is 4 ms. When the TTI is further shortened, adecoding time in the terminal apparatus is also shortened. When thedecoding time in the terminal apparatus is shortened, a remarkableadvantageous effect can be expected in a case in which real time isstrongly requested.

CITATION LIST Patent Literature

Patent Literature 1: JP 2009-212597A

DISCLOSURE OF INVENTION Technical Problem

In a case in which data is transmitted and received at a shorttransmission time interval shorter than an existing transmission timeinterval, a terminal apparatus can select a short transmission timeinterval with an optimum length by preparing a plurality of lengths(levels) of short transmission time intervals.

Accordingly, the present disclosure proposes a novel and improvedwireless communication apparatus, a novel and improved communicationmethod, a novel and improved computer program, and a novel and improvedwireless communication system capable of transmitting and receiving datain accordance with an optimum length of a short transmission timeinterval in a terminal apparatus among a plurality of lengths of a shirttransmission time interval at the time of transmission and reception ofdata at a short transmission time interval shorter than an existingtransmission time interval.

Solution to Problem

According to the present disclosure, there is provided a wirelesscommunication apparatus including: a frame generation unit configured togenerate a frame including a plurality of subframes; a transmission unitconfigured to transmit the generated frame to another communicationapparatus; and a notification unit configured to notify of informationregarding a plurality of lengths of a short transmission time intervalwhich is a transmission time interval shorter than one subframe periodin the subframe.

In addition, according to the present disclosure, there is provided awireless communication apparatus including: an acquisition unitconfigured to receive a frame including a plurality of subframes andacquire information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe from another communicationapparatus.

In addition, according to the present. disclosure, there is provided awireless communication method including: generating a frame including aplurality of subframes; transmitting the generated frame to anothercommunication apparatus and notifying of information regarding aplurality of lengths of a short transmission time interval which is atransmission time interval shorter than one subframe period in thesubframe.

In addition, according to the present disclosure, there is provided awireless communication method including: receiving a frame including aplurality of subframes; and acquiring information regarding a pluralityof lengths of a short: transmission time interval which is atransmission time interval shorter than one subframe period in thesubframe from a base station.

In addition, according to the present disclosure, there is provided acomputer program causing a computer to execute: generating a frameincluding a plurality of subframes; transmitting the generated frame toanother communication apparatus; and notifying of information regardinga plurality of lengths of a short transmission time interval which is atransmission time interval shorter than one subframe period in thesubframe.

In addition, according to the present disclosure, there is provided acomputer program causing a computer to execute: receiving a frameincluding a plurality of subframes; and acquiring information regardinga plurality of lengths of a short transmission time interval which is atransmission time interval shorter than one subframe period in thesubframe from a base station.

In addition, according to the present disclosure, there is provided awireless communication system including: a first communicationapparatus; and a second communication apparatus. The first communicationapparatus includes a frame generation unit configured to generate aframe including a plurality of subframes, a transmission unit configuredto transmit. the generated frame to the second communication apparatus,and a notification unit configured to notify the second communicationapparatus of information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe, and the second communicationapparatus includes an acquisition unit configured to receive the frameand acquire information regarding the plurality of lengths of the shorttransmission time interval in the subframe from the first communicationapparatus.

Advantageous Effects of Invention

According to the present disclosure, as described above, it is possibleto provide a novel and improved wireless communication apparatus, anovel and improved communication method, a novel and improved computerprogram, and a novel, and improved wireless communication system capableof transmitting and receiving data in accordance with an optimum lengthof a short transmission time interval in a terminal apparatus among aplurality of lengths of a short: transmission time interval at the timeof transmission and reception of data at a short transmission timeinterval shorter than an existing transmission time interval.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram illustrating a frame format of LTE.

FIG. 2 is an explanatory diagram illustrating a format of a downlink ofLTE.

FIG. 3 is an explanatory diagram illustrating an overview of schedulingof an uplink of LTE.

FIG. 4 is an explanatory diagram illustrating an example of aconfiguration of a system according to an embodiment of the presentdisclosure.

FIG. 5 is a block diagram illustrating an example of a configuration ofa base station 100 according to the embodiment.

FIG. 6 is a block diagram illustrating an example of a configuration ofa terminal apparatus 200 according to the embodiment.

FIG. 7 is an explanatory diagram illustrating an example of a short TTIfield.

FIG. 8 is an explanatory diagram illustrating an example of a short TTIfield.

FIG. 9 is an explanatory diagram illustrating an example of a short TTIfield.

FIG. 10 is an explanatory diagram illustrating an example of a short TTIfield.

FIG. 11 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodiment.

FIG. 12 is an explanatory diagram illustrating a method in which thebase station 100 notifies of whether information for a specific terminalapparatus is in a short TTI field.

FIG. 13 is an explanatory diagram illustrating a method in which thebase station 100 notifies of whether information for a specific terminalapparatus is in a short TTI field.

FIG. 14 is an explanatory diagram illustrating an example in which thebase station 100 notifies of whether information for a specific terminalapparatus is in a short TTI field using DCI inside a search space uniqueto the terminal apparatus 200 in a PDCCH.

FIG. 15 is an explanatory diagram illustrating a loan in which the basestation 100 notifies of a location of data of the short TTI in the shortTTI field using the DCI.

FIG. 16 is an explanatory diagram illustrating a form in which the basestation 100 notifies of a location of data of the short TTI in the shortTTI field using the DCI.

FIG. 17 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodiment.

FIG. 18 is an explanatory diagram illustrating a short TTI formed by 1OFDM symbol.

FIG. 19 is an explanatory diagram illustrating a short TTI formed by 2OFDM symbol.

FIG. 20 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodiment.

FIG. 21 is an explanatory diagram illustrating an example of a short TTIfield in 1 subframe.

FIG. 22 is an explanatory diagram illustrating a short TTI formed by 4OFDM symbols.

FIG. 23 is an explanatory diagram illustrating a short TTI formed by 4OFDM symbols in 1 frame.

FIG. 24 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodiment.

FIG. 25 is an explanatory diagram illustrating cm example in which shortTTIs with a plurality of levels coexist in one subframe.

FIG. 26 is an explanatory diagram illustrating another dispositionexample of short TTIs.

FIG. 27 is an explanatory diagram illustrating a disposition example ofshort TTIs.

FIG. 28 is an explanatory diagram illustrating a disposition example ofshort TTIs.

FIG. 29 is an explanatory diagram illustrating a disposition example ofshort TTIs.

FIG. 30 is an explanatory diagram illustrating a disposition example ofshort TTIs.

FIG. 31 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodiment.

FIG. 32 is an explanatory diagram illustrating a disposition example ofshort TTIs.

FIG. 33 is an explanatory diagram illustrating a disposition example ofshort TTIs.

FIG. 34 is an explanatory diagram illustrating a disposition example ofshort TTIs.

FIG. 35 is an explanatory diagram illustrating an example of a mapdisplayed on the terminal apparatus 200 of each user performing anetwork game.

FIG. 36 is an explanatory diagram illustrating a first slot RBG and asecond slot RBG which are in 1 subframe.

FIG. 37 is an explanatory diagram illustrating an allocation example ofshort TTIs to the terminal apparatus 200.

FIG. 38 is an explanatory diagram illustrating a form in which, normalTTIs and short TTIs are scheduled in one terminal apparatus 200.

FIG. 39 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodiment.

FIG. 40 is an explanatory diagram illustrating data of short TTIs putonly in the first 2 OFDM symbols among 11 OFDM symbols.

FIG. 41 is an explanatory diagram illustrating an example of a case inwhich each of 3 terminal apparatuses 200 decodes data of short TTIs.

FIG. 42 is an explanatory diagram illustrating an example in which theterminal apparatus 200 decodes all 11 short TTIs.

FIG. 43 is an explanatory diagram illustrating a destination of shortTTIs and an example of a result of CRC check in a certain terminalapparatus 200.

FIG. 44 is an explanatory diagram illustrating information transmittedtoward the terminal apparatus 200 by the base station 100.

FIG. 45 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodiment.

FIG. 46 is a block diagram illustrating an example of a configuration ofthe terminal apparatus 200 according to the embodiment.

FIG. 47 is an explanatory diagram illustrating an example of a short TTIfield.

FIG. 48 is an explanatory diagram illustrating an example of a short TTIfield.

FIG. 49 is an explanatory diagram illustrating an example of a short TTIfield.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and stricture aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted.

Note that the description will be made in the following order.

-   1. Embodiment of present disclosure-   1.1. Overview-   1.2. System configuration example-   1.3. Functional configuration example-   1.4. Operation examples-   1.4.1. First operation example-   1.4.2. Second operation example-   1.4.3. Third operation example-   1.4.4. Conclusion of operation examples-   2. Application examples-   2.1. Application examples for base station-   2.2. Application examples for terminal apparatus-   4. Conclusion

<1. Embodiment of Present Disclosure> [1.1. Ovetview]

An overview of an embodiment of the present disclosure will first bedescribed in the detailed description of the embodiment of the presentdisclosure. After the overview of the embodiment of the presentdisclosure is described, the embodiment of the present disclosure willbe described in detail.

FIG. 1 is an explanatory diagram illustrating a frame format of LTE. Asillustrated in FIG. 1, 1 radio frame of LTE includes 10 subframes. Thelength of 1 subframe is 1 ms. In addition, 1 subframe includes 14orthogonal frequency-division multiplexing (OFDM) symbols. A bandwidthis, for example, 2 MHz.

In LTE, data transmitted from a base station (eNodeB) has a combinationin which 1 transport block is formed with 1 subframe. In addition, acyclic redundancy Check (CRC) is suffixed to the end of a transportblock. That is, a terminal apparatus (user equipment: UE) receiving datatransmitted front the base station can decode data by receiving data of1 subframe. In other words, the UE can determine whether reception of atransport block succeeds by performing CRC. Accordingly, the UE performsACK or NACK on the data in 1 subframe to make a request ofretransmission referred to as a hybrid auto repeat request (ARQ). A UEresponds to the eNodeB with ACK in a case in which reception of datasucceeds. A UE responds to the eNodeB with NACK in a case in whichreception of data succeeds.

FIG. 2 is an explanatory diagram illustrating a format of a downlink ofLTE. In LTE, there are a plurality of resource blocks in 1 subframe. AneNodeB can allocate data to each UE in units of resource blocks. TheeNodeB stores control information for allocating data to each UE inunits of resource blocks in a control field disposed in the beginning ofthe subframe referred to as a physical downlink control channel (PDCCH).The PDCCH exists only in 1 subframe.

In LTE, a TTI is set to 1 ms to realize a high data rate. That is, theTTI is the same as the time of 1 subframe. A process latency when a UEdecodes a transport block in 1 subframe is about 4 subframes.Accordingly, the UE can respond to the eNodeB with ACK or NACK 4subframes after the received subframe. FIG. 3 is an explanatory diagramillustrating an overview of scheduling of an uplink of LTE. The PDCCH ofthe subframe received by the UE includes scheduling information of anuplink, but the scheduling information can be scheduled 4 subframesafter the received subframe. The reason why the scheduling informationcan be scheduled 4 subframes after the received subframe in this way isthat a process latency in the UE is considered.

Accordingly, when the TTI is shortened, shortening a latency fordecoding in the UE and a time for feedback to the eNodeB using an uplinkcan be expected. More specifically, when the TTI is shortened, thefollowing advantages can be expected.

First, when the TTI is shortened, control for a low latency of anapplication operating on the UE can be performed. When the TTI isshortened, a decoding time in UE is also shortened. Therefore, the UEcan shorten a time necessary for decision based on data transmitted fromthe eNodeB in a short transmission time interval (short TTI). Note that,in the following description, an existing TTI is also referred to as anormal TTI to distinguish the existing TTI from the short TTI.Accordingly, when the TTI is shortened, the UE can perform certaincontrol at low latency. For example, in a case in which a certainapplication that is strict on latency is activated in the UE for areason such as a strong request for real time, shortening a decodingtime is a considerable advantage. Even in a case in which the UE is anobject such as an automobile or a drone (a flying object that fliesautonomously), shortening the TTI is a considerable advantage since realtime is strongly requested.

Second, when the TTI is shortened, an RTT of a hybrid ARQ can bereduced. That is, when a decoding time is shortened, the UE can morequickly determine whether reception of data succeeds. When the UE canmore quickly determine whether reception of data succeeds, the UE canquickly respond to the eNodeB with ACK or NACK. Accordingly, when theTTI is shortened, the eNodeB can shorten a time taken untilretransmission of data which has not been received by the UE aftertransmission of the data to the UE, which leads to an improvement inthroughput. In a hybrid ARQ of LTE, when the UE does not succeed inreceiving data, subsequent data may not be transmitted. Therefore, quicktransmission of ACK from the UE to the eNodeB also contributes to animprovement in throughput.

Third, latency of feedback of a channel quality indicator (CQI) can bereduced when the TTI is shortened. The UE measures quality of a downlinkchannel on the basis of a reference signal supplied from the eNodeB andreports a measurement result of the quality to the eNodeB. Then, theeNodeB determines a modulation scheme for downlink data to the UE inconsideration of the quality of the downlink channel reported from theUE. When a latency of feedback from the UE is large, the eNodeBtransmits data in conformity with a modulation scheme corresponding toquality different from the original quality of the downlink to the UE.Accordingly, when a latency of the measurement of the quality of thedownlink channel and a latency of the report of the measurement resultcan be reduced, the eNodeB can reduce a time taken until an appropriatemodulation scheme for the UE is selected. When a time taken until theappropriate modulation scheme is selected can be reduced, an improvementin throughput of the downlink can be prospected.

By transmitting data at a short transmission time interval shorter thanan existing transmission time interval, it is possible to prospect theabove-described same advantageous effects, However, at the time of allsubstitution with transmission and reception of data at the shorttransmission time interval shorter than the existing transmission timeinterval, there is an influence on a terminal apparatus which can onlytransmit and receive data at the existing transmission time interval.Therefore, it is necessary to cause transmission and reception of dataat the existing transmission time interval and transmission andreception of data at the short transmission time interval to coexist.

Here, in a case in which transmission and reception of data at the shorttransmission time interval are caused to coexist with transmission andreception of data at the existing transmission time interval, atechnology for causing a terminal apparatus supporting transmission andreception of data at the short transmission time interval to perform aneffective reception process is necessary.

When a short TTI is introduced, a circuit necessary for decoding on areception side may not be reused. When certain data is received anddecoded and there is time to spare until subsequent data is received anddecoded, one multiplier can be used for calculation. However, when thereis no time to spare, one multiplier is not sufficient and a plurality ofmultipliers have to be prepared. Accordingly, to realize the short TTI,calculation cost of a. receiver increases and a hardware scale increasesin some cases. UEs connected to an eNodeB can be supplied from variousmakers. Depending on makers, there are cases in which hardware scalesare desired to be suppressed to be small and there are cases in whichtechniques for reducing hardware scales are desired. It is not knownwhether all the UEs can support the length of the same short TTI. Notethat, in the following description, the term “level” can be used as aterm meaning a difference in the length of the short TTI. Accordingly,when short TTIs with various levels are prepared on an eNodeB side,terminals supporting the short TTIs can be widespread.

In addition, even when UEs support the short TTIs, it is known, in thefirst place, whether all the UEs similarly request low latency.Requested latency times depend on high-order applications mounted onUEs. Accordingly, supply of a short TTI formed by 1 OFDM symbol to a UEnot requesting low latency to that extent leads to unnecessaryoccupation of resources.

Accordingly, in view of the above-mentioned circumstances, thedisclosers of the present disclosure have thoroughly examined atechnology in which an efficient reception process can be expected in a.terminal apparatus supporting transmission and reception of data at ashort transmission time interval in a case in which transmission andreception of data at a short transmission time interval are caused tocoexist with transmission and reception of data at an existingtransmission time interval. As a result, as will be described below, thedisclosers of the present disclosure have devised a technology in whichan effective reception process can be performed in a terminal apparatusby notifying the terminal apparatus of a location where data is inresources at a short transmission time interval in a case in whichtransmission and reception of data at the short transmission timeinterval are caused to coexist with transmission and reception of dataat an existing transmission time interval.

The overview of the embodiment of the present disclosure has beendescribed above. Next, the embodiment of the present disclosure will bedescribed in detail.

[1.2. System Configuration Example]

FIG. 4 is an explanatory diagram illustrating an example of aconfiguration of a system according to the embodiment of the presentdisclosure. Hereinafter, the example of the configuration of the systemaccording to the embodiment of the present disclosure will be describedwith reference to FIG. 4.

Referring to FIG. 4, a system 1 includes a base station 100 and aterminal apparatus 200. Herein, the base station 100 is also referred toas an eNodeB. In addition, herein, the terminal apparatus 200 is alsoreferred to as a user. The user can also be referred to as a userequipment (UE). Herein, the UE may be a UE as defined in LTE or LTE-A ormay be more generally a communication equipment.

(1) Base Station 100

The base station 100 is a base station of a cellular system (or a mobilecommunication system). The base station 100 performs wirelesscommunication with a terminal apparatus (for example, the terminalapparatus 200) located in a cell 10 of the base station 100. Forexample, the base station 100 transmits a downlink signal to theterminal apparatus and receives an uplink signal from the terminalapparatus.

(2) Terminal Apparatus 200

The terminal apparatus 200 can perform communication in a cellularsystem for a mobile communication system). The terminal apparatus 200performs wireless communication with a base station (for example, thebase station 100) of the cellular system. For example, the terminalapparatus 200 receives a downlink signal from the base station andtransmits an uplink signal to the base station. FIG. 4 illustrates fourterminal apparatuses 200A to 200D. Note that, in the followingdescription, when it is not necessary to distinguish the terminalapparatuses 200A to 200D from each other, the terminal apparatuses 200Ato 200D are referred to as terminal apparatuses 200.

[1.3. Functional Configuration Example]

Next, examples of functional configurations of the base station 100 andthe terminal apparatus 200 according to the embodiment of the presentdisclosure will be described with reference to FIGS. 5 and 6.

First, an example of a configuration of the base station 100 accordingto the embodiment of the present disclosure will be described withreference to FIG. 5. FIG. 5 is a block diagram illustrating an exampleof a configuration of a base station 100 according to the embodiment ofthe present disclosure. Referring to FIG. 5 the base station 100includes an antenna unit 110, a wireless communication unit 120, anetwork communication unit 130, a storage unit 140, and a processingunit 150.

(1) Antenna Unit 110

The antenna unit 110 radiates a signal output by the wirelesscommunication unit 120 as radio waves to a space. In addition, theantenna unit 110 converts the radio waves in the space into a signal andoutputs the signal to the wireless communication unit 120.

(2) Wireless Communication Unit 120

The wireless communication unit 120 transmits and receives a signal. Forexample, the wireless communication unit 120 transmits a downlink signalto the terminal apparatus and receives an uplink signal from theterminal apparatus.

(3) Network Communication Unit 130

The network communication unit 130 transmits and receives information.For example, the network communication unit 130 transmits information toanother node and receives information from the other node. For example,the other node includes another base station and a core network node.

(4) Storage Unit 140

The storage unit 140 temporarily or permanently stores various kinds ofdata and a program for operating the base station 100.

(5) Processing Unit 150

The processing unit 150 supplies various functions of the base station100. The processing unit 150 includes a transmission processing unit 151and a notification unit 153. Note that the processing unit 150 mayfurther include other constituent elements other than these constituentelements. That is, the processing unit 150 can also perform operationsother than the operations of the constituent elements.

The transmission processing unit 151 performs a process related totransmission of data destined for the terminal apparatus 200. Forexample, the transmission processing unit 151 generates a frame formedby a plurality of subframes and performs a process of transmitting thegenerated frame to the terminal apparatus 200. In addition, thenotification unit 153 performs a process related to notification ofinformation to the terminal apparatus 200. Note that specific operationsof the transmission processing unit 151 and the notification unit 153will be described in detail later.

Next, an example of a configuration of the terminal apparatus 200according to the embodiment of the present disclosure will be describedwith reference to FIG. 6. FIG. 6 is a block diagram illustrating anexample of a configuration of a terminal apparatus 200 according to theembodiment of the present disclosure. Referring to FIG. 6, the terminalapparatus 200 includes an antenna unit 210, a wireless communicationunit 220, a storage unit 230, and a processing unit 240.

(1) Antenna Unit 210

The antenna unit 210 radiates a signal output by the wirelesscommunication unit 220 as radio waves to a space. In addition, theantenna unit 210 converts the radio waves in the space into a signal andoutputs the signal to the wireless communication unit 220.

(2) Wireless Communication Unit 220

The wireless communication unit 220 transmits and receives a signal. Forexample, the wireless communication unit 220 receives a downlink signalfrom the base station and transmits an uplink signal to the basestation.

(3) Storage Unit 230

The storage unit 230 temporarily or permanently stores various kinds ofdata and a program for operating the terminal apparatus 200.

(4) Processing Unit 240

The processing unit 240 supplies various functions of the terminalapparatus 200. The processing unit 240 includes an acquisition unit 241,a reception processing unit 243, and a notification unit 245. Note thatthe processing unit 240 may further include other constituent elementsother than these constituent elements. That is, the processing unit 240can also perform operations other than the operations of the constituentelements.

The acquisition unit 241 performs, a process related to acquisition ofdata transmitted from the base station 100. The reception processingunit 243 performs a process related to reception of the data acquired bythe acquisition unit 241. The notification unit 245 performs a processrelated to notification of information to the base station 100. Notethat operations of the acquisition unit 241, the reception processingunit 243, and the notification unit 245 will be described in detaillater.

The examples of the functional configurations of the base station 100and the terminal apparatus 200 according to the embodiment of thepresent disclosure have been described with reference to FIGS. 5 and 6.Next, examples of operations of the base station 100 and the terminalapparatus 200 according to the embodiment of the present disclosure willhe described.

[1.4. Operation Examples] (1.4.1. First Operation Example)

First, a first operation example of the base station 100 and theterminal apparatus 200 according to the embodiment of the presentdisclosure will be described. As described above, in the case in whichtransmission and reception of data at the short transmission timeinterval are caused to coexist with transmission and reception of dataat the existing transmission time interval, a technology for causing aterminal apparatus corresponding to transmission and reception of dataat the short transmission time interval to perform an effective processis necessary. In the first operation example, an example of an operationin which the terminal apparatus corresponding to transmission andreception of data at the short transmission time interval can perform aneffective process will be described.

In a case in which transmission and reception of data in the short TTIare caused to coexist with transmission and reception of data in theexisting TTI, it is necessary for the base station 100 to inform theterminal apparatus 200 of a location where a resource to be used totransmit or receive data is in the short TTI. With regard to a locationof the resource to be used to transmit or receive data in the short TTI,semi-static informing method and a dynamically informing method can beconsidered. In the method of notifying each terminal apparatus 200 of aresource in the semi-static manner, a downlink resource for one terminalapparatus 200 is fixedly allocated in the semi-static manner. Therefore,the downlink resource may be wasteful in a case in which transmissionand reception of data in the short TTI are not used. On the other hand,in the method of notifying each terminal apparatus 200 of a resourcedynamically, control information to he measured by the terminalapparatus 200 increases. A control field (PDCCH) may be short when thenumber of terminal apparatuses 200 located in the cell 10 increases.

Accordingly, when resources of the short TTI are allocated, the basestation 100 takes three methods, (1) a method of notifying of a locationwhere a field (short TTI field) for performing transmission andreception of data is in the short TTI, (2) a method of notifying whetherthere is information destined for a specific terminal apparatus in theshort TTI field, and (3) a method of notifying of a resource of theshort TTI for each terminal apparatus. Note that all the three methodsmay not be said to be essential in the base station 100. Hereinafter,the details of the three methods will be described.

(1) Method of Notifying of Location Where Short TTI Field is

First, the method of notifying of a location where the short TTI fieldis will be described. The base station 100 notifies the terminalapparatus 200 of the short TTI field in one subframe in a semi-staticmanner, for example, using system information for which broadcast isused or a dedicated signal for each terminal apparatus 200. Here,“semi-static” means that a short TTI field is not changed before thebase station 100 designates the short TTI field again, but the short TTIfield is changeable. Note that a plurality of short TTI field may be inone subframe.

The base station 100 notifies the terminal apparatus 200 of the shortTTI field in one subframe in the semi-static manner. At this time point,however, the base station 100 does not notify of a way in which eachterminal apparatus 200 uses the short TTI field.

FIG. 7 is an explanatory diagram illustrating an example of a short TTIfield. Reference numeral 301 in FIG. 7 denotes a short TTI fielddesignated in a physical downlink shared channel (PDSCH) in onesubframe. FIG. 7 illustrates an example in which the TTI in a frequencydomain of a part of a bandwidth of 20 MHz is set to have the samelength, as 1 OFDM symbol.

As described above, the plurality of short TTI fields may be in onesubframe. FIG. 8 is an explanatory diagram illustrating an example ofthe short TTI field. FIG. 8 illustrates an example in which two shortTTI fields are in one subframe. Reference numerals 301 and 302 denoteshort TTI fields designated in the PDSCH in one subframe. The short TTIfield denoted by reference numeral 301 spans the whole PDSCH and theshort TTI field denoted by reference numeral 302 is in the PDSCHequivalent to the second half 7 OFDM symbols. In addition, FIG. 8illustrates an example in which the resource of the short TTI fielddenoted by reference numeral 302 is greater than the resource of theshort TTI field denoted by reference numeral 301.

In addition, the short TTI field may be in all the subframes or theshort TTI field may be in a specific subframe of 1 frame. This isbecause there is an application in which the short TTI field which isnecessary for all the subframes and there is also an application inwhich the short TTI field suffices to be in a specific subframe of 1frame.

For example, the base station 100 transmits a control signal in aspecific location in 1 frame to the terminal apparatus 200. However, ause case in which, the terminal apparatus 200 is expected to decode thecontrol signal in a short time is considered. This use case is a usecase in which the base station 100 uses the short TTI field as a fieldfor transmitting the control signal of the terminal apparatus 200. Thecontrol signal of the terminal apparatus 200 to be transmitted in theshort TTI field by the base station 100 may be a signal for controllingan application or may be a control signal for receiving a wirelesssignal.

As described above, the short TTI field may be in all the subframes orthe short TTI field may be in a specific subframe of 1 frame. Inaddition, the base station 100 may change the short TTI field for eachsubframe. The base station 100 can improve the degree of freedom ofsetting by changing the short TTI field for each subframe.

FIG. 9 is an explanatory diagram illustrating an example of a short TTIfield. FIG. 9 illustrates an example in which the base station 100 setsthe short TTI field denoted by reference numeral 302 in advance and thebase station 100 dynamically sets whether data of the short TTI is acttally put in the short TTI field with downlink control information (DCI)in the PDCCH denoted reference numeral 303.

The base station 100 can prevent resources from being wasteful due tonormally fixed disposition of the short TTI field by setting whetherdata is in the short TTI field with the DCI in the PDCCH denoted byreference numeral 303. That is, even when the short TTI field is set,the base station 100 may normally not put data of the short TTI andtransmit the data in the short TTI field. Therefore, it is possible toset whether data is in the short TTI field with the DCI in the PDCCH toprevent resources from being wasteful.

FIG. 10 is an explanatory diagram illustrating an example of a short TTIfield. FIG. 10 illustrates, an example of a case in which, as in FIG. 9,the base station 100 sets the short TTI field denoted by referencenumeral 302 in advance and the base station 100 dynamically sets whetherdata of the short TTI is actually put in the short TTI field with theDCI in the PDCCH denoted by reference numeral 303.

The example illustrated in FIG. 10 is different from the exampleillustrated in FIG. 9 in that presence or absence of data in the shortTTI field of another subsequent subframe is set with DCI in the PDCCHdenoted by reference numeral 303 rather than the same subframe. In theexample illustrated in FIG. 9, since presence or absence of data in theshort TTI field of the same subframe is set with DCI in the PDCCH, theterminal apparatus 200 has to decode the PDCCH and instantaneouslydetermine the presence or absence of data in the short TTI field of thesame subframe. In the example illustrated in FIG. 10, since presence orabsence of data in the short TTI field of another subsequent subframe isset with DCI in the PDCCH, the terminal apparatus 200 knows whether thedata of the short TTI is in the short TTI field at a time point at whichthe short TTI field of the other subsequent subframe arrives.Accordingly, in the example illustrated in FIG. 10, the terminalapparatus 200 can instantaneously start the decoding, when there is thedata of the short TTI at the time point at which the short TTI field ofthe other subsequent subframe arrives.

FIG. 11 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure. FIG. 11 illustrates an example of anoperation of the base station 100 when the base station 100 notifies theterminal apparatus 200 of a field which is likely to be used as theshort TTI and notifies the terminal apparatus 200 that the notifiedfield is used as the short TTI. Hereinafter, an operation example of thebase station 100 and the terminal apparatus 200 according to theembodiment of the present disclosure will be described with reference toFIG. 11.

The base station 100 notifies the terminal apparatus 200 of the shortTTI field (which is a field which is likely to be the short TTI) in thesubframe (step S101). For example, the notification unit 153 performsthe process of step S101. The base station 100 notifies the terminalapparatus 200 of a field which is likely to be used as the short TTI inone subframe in the semi-static manner using system information forwhich broadcast is used or a dedicated signal for each terminalapparatus 200.

When the terminal apparatus 200 is notified of the field which is likelyto be the short TTI, subsequently, the base station 100 dynamicallynotifies the terminal apparatus 200 that the field which is likely to bethe short TTI is actually used as the short TTI for each subframe (stepS102). For example, e notification unit 153 performs the process of stepS102. For example, tare base station 100 designates whether the fieldwhich is likely to be used as the short 111 is actually used as theshort TTI in DCI in the PDCCH, as described above.

The base station 100 operates in this way. Thus, the base station 100can efficiently use resources. In a case in which the field which islikely to be the short TTI is actually used as the short TTI, theterminal apparatus 200 may perform an operation for the short TTI.Therefore, a reception process can be efficient.

(2) Method of Notifying Whether There is Information Destined forSpecific Terminal Apparatus in Short TTI Field

Next, a method of notifying whether information designed for a specificterminal apparatus in the short TTI field is in the short TTI field willbe described. For example, the base station 100 dynamically notifieseach terminal apparatus 200 whether there is information addressed tothe terminal apparatus 200 in the short TTI field notified of in thesemi-static method. For example, the base station 100 notifies theterminal apparatus 200 whether there is information addressed to theterminal apparatus 200 in the short TTI field, in a semi-static mannerusing the dedicated signaling or dynamically using the PDCCH. When thebase station 100 performs the notification in the semi-static mannerusing the dedicated signaling, the base station 100 can notify theterminal apparatus 200 whether there is the information addressed to theterminal apparatus 200 in the short TTI field without changing existingDCL. In addition when the base station 100 performs the notificationdynamically using the PDCCH, the base station 100 may put data of theshort TTI the short TTI field only in a case in which the data of theshort TTI is transmitted. Therefore, resources can be efficiently used.

At this time, the base station 100 notifies the terminal apparatus 200only whether there is the information addressed to the terminalapparatus 200 in the short TTI field. Whether there is data related ineach terminal apparatus 200 in the short TTI field is preferablydetermined with small labor by the terminal apparatus 200. This isbecause power consumption can be reduced since it is not necessary forthe terminal apparatus 200 for which there is no data in the short TTIfield to decode the data of the short TTI.

FIG. 12 is an explanatory diagram illustrating a method in which thebase station 100 notifies of whether information destined for a specificterminal apparatus is in a short TTI field. FIG. 12 illustrates a formin which it is notified whether information destined for a specificterminal apparatus is in the short TTI field in the same subframe in thePDCCH of the subframe.

FIG. 13 is an explanatory diagram illustrating a method in which thebase station 100 notifies of whether information for a specific terminalapparatus is in a short TTI field. FIG. 13 illustrates a form in whichthe base station 100 notifies the terminal apparatus 200 whether theinformation destined for the specific terminal apparatus is in the shortTTI field in a subsequent subframe in the PDCCH of the subframe.

A method illustrated in FIG. 13 is the same method as the methodillustrated in FIG. 12, but the base station 100 can advance a starttiming of decoding of the data of the short TTI in the terminalapparatus 200 by notifying the terminal, apparatus 200 whether theinformation destined for the specific terminal apparatus is in the shortTTI field of the subsequent subframe in the PDCCH of the subframe.

When the base station 100 notifies the terminal apparatus 200 whetherthe information destined for the specific terminal apparatus is in theshort TTI field, the base station 100 may perform designation using DCIinside a search space unique to the terminal apparatus 200 in the PDCCH(or ePDCCH). FIG. 14 is an explanatory diagram illustrating an examplein which the base station 100 notifies of whether information for aspecific terminal apparatus is in a short TTI field using DCI inside asearch space unique to the terminal apparatus 200 in the PDCCH.

When the base station 100 performs the not dynamically using the PDCCH,the base station 100 may put the data of the short TTI in the short TTIfield only in the case in which the data of the short is transmitted.Therefore, resources can be efficiently used. In addition, whether thereis data related in each terminal apparatus 200 in the short TTI field ispreferably determined with small labor by the terminal apparatus 200. Inaddition, this is because power consumption can be reduced since it isnot necessary for the terminal apparatus 200 for which there is no datain the short TTI field to decode the data of the short TTI.

(3) Method of Notifying of Resource of the Short TTI for Each TerminalApparatus

The base station 100 may notify the terminal apparatus 200 whether thedata of the short TTI is in the short TTI field, using DCI. At the timeof notification, the base station 100 may also notify the terminalapparatus 200 of a resource of the short TTI field which is data of theshort TTI to be received and decoded by the target terminal apparatus200.

FIG. 15 is an explanatory diagram illustrating a form in which the basestation 100 notifies of a location of data of the short TTI in the shortTTI field using DCI. In the example illustrated in FIG. 15, a locationdenoted by reference numeral 305 in the same subframe is assumed to be alocation where the data of the short TTI to be received and decoded bythe target terminal apparatus 200 is. The base station 100 notifies thetarget terminal apparatus 200 that the data of the short TTI to bedecoded is in the location denoted by reference numeral 305, using DCI.By performing the notification in this way, the terminal apparatus 200receiving DCI can perform decoding with reference to only the location.

FIG. 16 is an explanatory diagram illustrating a form in which the basestation 100 notifies of a location of data of the short TTI in the shortTTI field using DCI. In the example illustrated in FIG. 16, the locationdenoted by reference numeral 305 in the subsequent subframe is assumedto be a location where the data of the short TTI to be received anddecoded by the target terminal apparatus 200 is. The base station 100notifies the target terminal apparatus 200 that the data of the shortTTI to be decoded is in the location denoted by reference numeral 305,using DCI. By performing the notification in this way, the terminalapparatus 200 receiving DCI can perform decoding with reference to onlythe location.

Note that the base station 100 may notify the terminal apparatus 200 ofinformation regarding the short TTI using ePDCCH in which the controlsignal is put in a part of the PDSCH rather than the PDCCH. In a case inwhich the notification is performed using ePDCCH, the base station 100may notify the terminal apparatus 200 of the information regarding theshort TTI in the same subframe or may notify the terminal apparatus 200of the information regarding the short TTI in the subsequent subframe.

FIG. 17 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure. FIG. 17 illustrates an operation example ofthe base station 100 and the terminal apparatus 200 when the basestation 100 notifies the terminal apparatus 200 of a field which islikely to be used as the short TTI and then the terminal apparatus 200returns ACK or NACK of the received data. Hereinafter, an operationexample of the base station 100 and the terminal apparatus 200 accordingto the embodiment of the present disclosure will be described withreference to FIG. 17.

The base station 100 notifies the terminal apparatus 200 of the shortTTI field (which is a field which is likely to be the short TTI) in thesubframe (step S101). For example, the notification unit 153 performsthe process of step S101. The base station 100 notifies the terminalapparatus 200 of a field which is likely to he used as the short TTI inone subframe in the semi-static manner using system information forwhich broadcast is used or a dedicated signal for each terminalapparatus 200.

When the terminal apparatus 200 is notified of the field which is likelyto be the short TTI, subsequently; the base station 100 dynamicallynotifies the terminal apparatus 200 that the field which is likely to bethe short TTI is actually used as the short TTI for each subframe (stepS102), For example, the notification unit 153 performs the process ofstep S102. For example, the base station 100 designates whether thefield which is likely to be used as the short TT1 is actually used asthe short in DCI in the PDCCH, as described above.

Subsequently, the base station 100 notifies the terminal apparatus 200of presence or absence of a resource for the specific terminal apparatus200 in the short TTI (step S103). For example, the notification unit 153performs the process of step S103.

Subsequently, the base station 100 notifies the terminal apparatus 200of a location of the resource to be received by the specific terminalapparatus 200 in the short TTI (step S104). For example, thenotification unit 153 performs the process of step S104.

Subsequently, the base station 100 puts the data of the short TTI in thelocation of the resource notified of in the foregoing step S104 totransmit the data to the terminal apparatus 200 (step S105). Forexample, the transmission processing unit 151 performs the process ofstep S105 by transmitting the data from the wireless communication unit120 via the antenna unit 110.

The terminal apparatus 200 decodes the data of the short TTI transmittedfrom the base station 100 in the foregoing step S105 on the basis of theinformation of which the base station 100 notifies the terminalapparatus 200 in the, foregoing steps S101 to S104 (step S106). Forexample, the reception processing unit 243 performs the process of stepS106.

When the terminal apparatus 200 decodes the data of the short TTI instep S106, the terminal apparatus 200 each notifies the base station 100of ACK at the time of success of the decoding and notifies the basestation 100 of NACK at the time of failure of the decoding (step S107).For example, the notification unit 245 performs the process of stepS107.

In the related art, an eNodeB designates an individual resource of eachUE in DCI of the PDCCH. However, the resource of the short TTI isspecial unlike a resource of a TTI of the related art. Since the specialshort TTI may not normally be present, the short TTI field is preferablyvariable to some extent. However, when a short TTI field and a normalTTI field are not ensured, a resource may not directly be designatedfrom the PDCCH, and thus it is difficult to directly designate theresource of the short TTI from the PDCCH.

Accordingly, in a first operation example of the embodiment, the basestation 100 designate the short TTI field in the semi-static manner anddynamically designates whether there is the short TTI field. The basestation 100 notifies the terminal apparatus 200 whether there is thedata of the short TTI of the terminal apparatus 200 in accordance with adynamic method using the the PDCCH or a semi-static method usingdedicated signaling. By performing the notification in this way, aresource of the normal TTI and a resource of the short TTI can beeffectively managed in accordance with a method of directly designatingall the resources in the PDCCH of the related art than m the relatedart.

In the first operation example of the embodiment, the base station 100can control an application mounted on the terminal apparatus 200 in alow latency and in a good response by designating the short TTI field inthe semi-static manner and dynamically designating whether there is theshort TTI field. In addition, in the first operation example of theembodiment, the terminal apparatus 200 can return ACK or NACK quickly,and thus an improvement in throughput is prospected. Then, in the firstoperation example of the embodiment, since the resource of the short TTIcan effectively coexist with the resource of the normal TTI, theresources are not wasteful and an improvement in throughput can begreatly expected.

(1.4.2. Second Operation Example)

Next, a second operation example of the base station 100 and theterminal apparatus 200 according to the embodiment of the presentdisclosure will be described. As described above, in the case in whichtransmission and reception of data at the short transmission timeinterval are caused to coexist with transmission and reception of dataat the existing transmission time interval terminal apparatusescorresponding to the short TTIs can be widespread when short TTIs withvarious levels are prepared on an base station side. In the secondoperation example, an operation example of the base station 100 and theterminal apparatus 200 when short TTIs with various levels are preparedwill be described.

F1G. 18 is an explanatory diagram illustrating a short TTI formed by 1OFDM symbol. The short TTI formed by 1 OFDM symbol is also referred toas a short TTI with level 1. In addition, FIG. 19 is an explanatorydiagram illustrating a short TTI formed by 2 OFDM symbols. The short TTIformed by 2 OFDM symbols is also referred to as a short TTI with level2.

In a case in which the level of the short TTI is 1, a resource of LTE isoccupied wastefully and the whole throughput deteriorates. The reasonwhy the throughput deteriorates is that there is a case in which thesame level of the short TTI is not necessary in all the terminalapparatuses 200 corresponding to the short TTIs. In addition, all theterminal apparatuses 200 corresponding to the short TTIs may not be saidto similarly realize the levels of the short TTIs. Accordingly, when acommunication service provider prepares a plurality of levels of theshort TTIs, the terminal apparatuses 200 corresponding to the short TTIsmanufactured by various vendors (makers) can be connected to an LETnetwork in which the plurality of levels of the short TTIs are prepared.

The base station 100 prepares the plurality of levels of the short TTIs.Setting of the levels of the short TTIs may differ for each cell. Thebase station 100 notifies the terminal apparatuses 200 of the pluralityof levels of the short TTIs supplied by the base station 100 using, forexample, system information in a broadcast.

The terminal apparatus 200 notifies the base station 100 of a processingability (for example, a hardware ability, a category of an applicationto be executed, or a capability of the terminal apparatus 200). Inaddition, the terminal apparatus 200 may set a latency level requestedfor each application to be executed. This is because there is a case inwhich a low latency is not requested depending on an application to beexecuted by the terminal apparatus 200 even when the terminal apparatus200 has an ability to perform a process in a low latency.

The terminal apparatus 200 may process data of the short TTIs with theplurality of levels even when the short TTIs with the plurality oflevels coexist with the same subframe. In addition, the terminalapparatus 200 may process data of normal TTIs and data of short TTIs inparallel.

FIG. 20 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure. Hereinafter, an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure will be described with reference to FIG. 20.

The base station 100 supplies the suppliable levels of the short TTIs tothe terminal apparatuses 200 located in the cell in the broadcast (stepS201). For example, the notification unit 153 performs the process ofstep S201.

The terminal apparatus 200 receiving the levels of the short TTIssuppliable by the base station 100 from the base station 100 notifiesthe base station 100 of a capability with which the short TTIs can beprocessed (step S202). For example, the notification unit 245 performsthe process of step S202. In step S202, the terminal apparatus 200 maynotify the base station 100 of information regarding a hardwareprocessing ability.

In addition, the terminal apparatus 200 requests the base station 100 tosupply the levels of the short TTIs in accordance with a purpose of amounted application (step S203). For example, the notification unit 245performs the process of step S203.

When the base station 100 receives the capability with which the shortTTIs can be processed and the request for the levels of the short TTIsfrom the terminal apparatus 200, the base station 100 selects the levelsof the short TTIs on the basis of the received content and transmits thedata of the short TTI to the terminal apparatus 200 in accordance with aselected level using the resource of the short TTI (step S204). Forexample, the transmission processing unit 151 performs the process ofstep S204 by transmitting the data from the wireless communication unit120 via the antenna unit 110.

The base station 100 according to the embodiment of the presentdisclosure operates in this way, and thus can select the level of theshort TTI in accordance with the request and the ability of the terminalapparatus 200. In addition, the terminal apparatus 200 according to theembodiment of the present disclosure can receive the data of the shortTTI at the level in accordance with the ability of the terminalapparatus 200 or the request of the application to be executed byperforming the notification in this way.

Some of the terminal apparatuses 200 can also be considered to permit alatency time although the latency time is longer than the level evenwhen the data is received at a low level of the short TTI. FIG. 21 is anexplanatory diagram illustrating an example of a short TTI field in 1subframe. For example, certain terminal apparatuses 200 are assumed topermit a latency of 2 OFDM symbols, even when data is received at level1 of the short TTI. In this case, the base station 100 causes thecertain terminal apparatuses 200 to use every other OFDM symbol as theshort TTIs, as illustrated in FIG. 21. The OFDM symbol denoted byreference numeral 311 is an OFDM symbol which is used the terminalapparatus 200 as the short TTI. In this way, the base station 100 canefficiently supply the resources to the terminal apparatuses 200 capableof permitting the latency of 2 OFDM symbols by causing the terminalapparatuses 200 to use the short TTI fields at every other OFDM symbol.

The short TTI field illustrated in FIG. 21 is different from the shortTTI formed by 2 OFDM symbols illustrated in FIG. 19 and the resource ofthe short TTI formed by 1 OFDM symbol is decimated. The base station 100can cause another terminal apparatus 200 to use the decimated resource(the OFDM symbol denoted by reference numeral 312). That is, the basestation 100 lowers the level of the latency control by decimating theresource of the short TTI formed by 1 OFDM symbol at every other OFDMsymbol. Note that the terminal apparatus 200 requesting the latency of 1OFDM symbol may receive the data of the short TTI from the base station100 using the resource of a certain OFDM symbol denoted by referencenumeral 311 or 312 in FIG. 21.

The short TTI formed by 2 OFDM symbols illustrated in FIG. 19 iscompleted with one subframe. However, a short TTI formed by, forexample, 4 OFDM symbols may not be completed with one subframe. FIG. 22is an explanatory diagram illustrating a short TTI formed by 4 OFDMsymbols. Since the short TTI with level 4 at which the short TTI isformed by 4 OFDM symbols may not be completed with one subframe, asillustrated in FIG. 22, a portion straddling two frames occurs. In thiscase, the base station 100 notifies the terminal apparatus 200 whetherdata of the short TTI straddles two frames.

As a system frame number (SFN), an integer from 0 to 1023 is repeated.In addition, there are 10 subframes in one frame. FIG. 23 is anexplanatory diagram illustrating a short TTI formed by 4 OFDM symbols in1 frame. In a case in which a short TTI is formed by 4 OFDM symbols, asillustrated in FIG. 23, a short TTI formed by 4 OFDM symbols is disposedto straddle a first subframe and a second subframe. That is, the shortTTI formed by 4 OFDM symbols is disposed to straddle an odd subframe andan even subframe. Accordingly, when the base station 100 can notify theterminal apparatus 200 of a relation between a system frame number and asubframe number, and a phase of the short TTI, the terminal apparatus200 can normally receive the short TTI of 4 OFDM symbols.

SFN is transmitted with a broadcast signal called a master informationblock (MIB) from the base station 100 to the terminal apparatus 200.Accordingly, the base station 100 fixes the relation between the systemframe number and the subframe number, and the phase of the short TTI inadvance or separately notifies the terminal apparatuses 200 of therelation between the system frame number and the subframe number, andthe phase of the short TTI by signaling. The base station 100 may notifythe terminal apparatuses 200 of the relation between the system framenumber and the subframe number, and the phase of the short TTI only in acase in which the short TTI may not be completed with one subframe likethe short TTI with 4 OFDM symbols.

FIG. 24 a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure. FIG. 24 illustrates an operation example ofthe base station 100 and the terminal apparatus 200 in a case in whichthe short TTI may not be completed with one subframe. Hereinafter, anoperation example of the base station 100 and the terminal apparatus 200according to the embodiment of the present disclosure will be describedwith reference to FIG. 24.

The base station 100 supplies the system frame number such as MIB to theterminal apparatus 200 in a broadcast (step S211). For example, thenotification, unit 153 performs the process of step S211.

Subsequently the base station 100 supplies the suppliable levels of theshort TTIs to the terminal apparatuses 200 located in the cell in thebroadcast (step S212). For example, the notification unit 153 performsthe process of step S212.

Subsequently, the base station 100 supplies a correspondence relationbetween the short TTI of each level, and the system frame number and thesubframe number to the terminal apparatus 200 in a broadcast or bydedicated signaling (step S213). For example, the notification unit 153performs the process of step S213. Note that the correspondence relationbetween the short TTI of each level, and the system frame number and thesubframe number to the terminal apparatus 200 may be fixed in advance ina specification.

The terminal apparatus 200 receiving the levels of the short TTIssuppliable by the base station 100 notifies the base station 100 of acapability with which the short TTIs can be processed (step S214). Forexample, the notification unit 245 performs the process of step S214.

In addition, the terminal apparatus 200 requests the base station 100 tosupply the levels of the short TTIs in accordance with a purpose of amounted application (step S215). For example, the notification unit 245performs the process of step S215.

When the base station 100 receives the capability with which the shortTTIs can be processed and the request for the levels of the short TTIsfrom the terminal apparatus 200, the base station 100 selects the levelof the short TTI on the basis of the received content and transmits thedata of the short TTI to the terminal apparatus 200 in accordance with aselected level using the resource of the short TTI (step S216). Forexample, the transmission processing unit 151 performs the process ofstep S216 by transmitting the data from the wireless communication unit120 via the antenna unit 110.

When the terminal apparatus 200 receives the data of the short TTI fromthe base station 100, the terminal apparatus 200 decodes the data of theshort TTI on the basis of the correspondence relation received in stepS213 from the base station 100.

The base station 100 according to the embodiment of the presentdisclosure operates in this way, and thus can select the level of theshort TTI in accordance with the request and the ability of the terminalapparatus 200 and can cause the terminal apparatus 200 to normallydecode the data of the short TTI. In addition, the terminal apparatus200 according to the embodiment of the present disclosure can receivethe data of the short TTI at the level in accordance with the ability ofthe self-apparatus and the request of the application to be executed andcan normally decode the data of the short TTI by performing thenotification in this way.

The short TTIs with the plurality of levels may coexist with onesubframe. FIG. 25 is an explanatory diagram illustrating an example inwhich the short TTIs with the plurality of levels coexist with onesubframe.

FIG. 25 illustrates an example in which the short TTI with level 4formed by 4 OFDM symbols and the short TTI with level 2 formed by 2 OFDMsymbols coexist with one subframe. In the example of FIG. 25, threeshort TTIs with level 4 are continuously disposed and one short TTI withlevel 2 is subsequently disposed in the first subframe, and one shortTTI with level 2 is first disposed and three short TTIs with level 4 aresubsequently continuously disposed in a subsequent subframe. Of course,a disposition pattern is not limited to the related example. The shortTTIs with different levels may be disposed to coexist in the samepattern, in all the subframes. For example, in all the subframes, threeshort TTIs with level 4 may be continuously disposed and one short TTIwith level 2 may be subsequently disposed. In addition, for example, inall the subframes, one short TTI with level 2 may be first disposed andthree short TTIs with level 4 may be subsequently continuously disposed.

FIG. 26 is an explanatory diagram illustrating another dispositionexample of the short TTIs. In a subframe, typically, the PDCCH in whicha control signal can be stored is disposed in a beginning portion andthe PDSCH in which user data can be stored is disposed after the PDCCH.For example, as illustrated in FIG. 26, it can be considered that theshort TTIs are set as the succeeding the PDSCH using 3 OFDM symbols asthe PDSCH. In this case, when only the short TTIs with level 2 are used,the final 1 OFDM symbol of the subframe may not be used as the short TTIwith level 2. Accordingly, as illustrated in FIG. 26, the final 1 OFDMsymbol of the subframe may be used as the short TTI with level 1. Notethat, as illustrated in FIG. 26, the base station 100 may divide aresource of a certain OFDM symbol into the short TTI with level 1 andthe short TTI with level 2 for use.

FIG. 27 is an explanatory diagram illustrating a disposition example ofthe short TTIs. The disposition example of the short TTIs illustrated inFIG. 27 is different from the disposition example of the short TTIsillustrated in FIG. 26 in that no short TTI is disposed in a resource inwhich the short TTI with level 2 is disposed in the final 1 OFDM symbolof the subframe.

As illustrated in FIGS. 26 and 27, the base station 100 may divide theresource of a certain OFDM symbol into the short TTI with level 1 andthe short TTI with level 2 for use and may also change an amount ofresource allocated to the short TTIs. FIGS. 26 and 27 illustrateexamples in which an amount of resource allocated to the short TTIs withlevel 2 is relatively greater than an amount of resource allocated tothe short TTIs with level 1. The base station 100 may change the amountof resource allocated to the short TTIs with each level in accordancewith, for example, a demand from the terminal apparatuses 200.

As illustrated in FIGS. 26 and 27, in a case in which the short TTIs aredisposed only in the portion PDSCH without disposing the short TTIs inthe portion PDCCH, the length of the PDCCH is variable from 1 OFDMsymbol to 3 OFDM symbols. The base station 100 can notify the terminalapparatuses 200 of information regarding the length of the PDCCH(information regarding the number of OFDM symbols) using a physicalcontrol format indicator channel (PCFICH) in the PDCCH. Since the lengthof the PDCCH is variable from 1 OFDM symbol to 3 OFDM symbols, thelength of the PDSCH is variable from 11 OFDM symbols to 13 OFDM symbols.Accordingly, in a case in which the short TTIs are disposed only in theportion PDSCH, the terminal apparatus 200 is preferably informed of arelation between a disposition pattern of the short TTIs and thevariable PDSCH.

FIG. 28 is an explanatory diagram illustrating a disposition example ofthe short TTIs. FIG. 28 illustrates a disposition example of the shortTTIs in a case in which the length of the PDCCH is 3 OFDM symbols, thatis, the length of the PDSCH is 11 OFDM symbols. In the exampleillustrated in FIG. 28, the resource of one OFDM symbol is divided intothe short TTI with level 1 and the short TTI with level 2 for use.

FIG. 29 is an explanatory diagram illustrating a disposition example ofthe short TTIs. FIG. 29 illustrates a disposition example of the shortTTIs in a case in which the length of the PDCCH is 2 OFDM symbols, thatis, the length of the PDSCH is 12 OFDM symbols. In the exampleillustrated in FIG. 29, the resource of one OFDM symbol is divided intothe short TTI with level 1 and the short TTI with level 2 for use.

FIG. 30 is an explanatory diagram illustrating a disposition example ofthe short TTIs. FIG. 30 illustrates a disposition example of the shortTTIs in a case in which the length of the PDCCH is 1 OFDM symbol, thatis, the length of the PDSCH is 13 OFDM symbols. In the exampleillustrated in FIG. 30, the resource of one OFDM symbol is divided intothe short TTI with level 1 and the short TTI with level 2 for use.

In a case in which the disposition pattern of the short TTIs is changedin accordance with the length of the PDCCH (that is, the length of thePDSCH), the base station 100 notifies the terminal apparatuses 200 of arelation between the disposition pattern of the short TTIs and the PDSCHin advance. Then, the base station 100 notifies the terminal apparatuses200 of information regarding, the length of the PDCCH using PCFICH. Whenthe terminal apparatuses 200 know the information regarding the lengthof the PDCCH, the terminal apparatuses 200 can know which dispositionpattern of the short TTIs is used.

FIG. 31 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure. Hereinafter, an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure will be described with reference to FIG. 31.

The base station 100 first notifies the terminal apparatus 200 of thedisposition pattern of the short TTIs corresponding to PCFICH (stepS221). For example, the notification unit 153 performs the notificationof step S221. The disposition pattern of the short TTIs corresponding toPCFICH may be fixed in advance in the specification.

Subsequently, the base station 100 notifies the terminal apparatus 200of the information regarding the length of the PDCCH with the PCFICH(step S222). For example, the notification unit 153 performs thenotification of step S222.

Subsequently; the base station 100 supplies the short TTIs correspondingto PCFICH (step S223). For example, the transmission processing unit 151performs the process of step S223 by transmitting data from the wirelesscommunication unit 120 via the antenna unit 110. For example, in a casein which the disposition pattern of the short TTIs in a case in whichthe length of the PDCCH is 3 OFDM symbols is the pattern illustrated inFIG. 28, the base station 100 supplies the short TTIs at the dispositionpattern of the short TTIs illustrated in FIG. 28.

When the terminal apparatus 200 knows the disposition pattern of theshort TTIs corresponding to PCFICH and receives the notification of theinformation regarding the length of the PDCCH with PCFICH, the terminalapparatus 200 determines the disposition of the short TTIs correspondingto PCFICH and performs a process of decoding the data of the short TTIs(step S224). For example, the reception processing unit 243 performs theprocess of step S224.

The terminal apparatus 200 can know which disposition pattern of theshort TTIS is used since the terminal apparatus 200 knows theinformation regarding the length of the PDCCH by performing theabove-described process. Then, the terminal apparatus 200 can, performthe appropriate process of decoding the data of the short TTIs since theterminal apparatus 200 knows the disposition pattern of the short TTIsin advance.

For example, as described with reference to FIG. 21, in a case in whichthe short TTIs are disposed intermittently by decimating the levels ofthe short TTIs at every other OFDM symbol, the disposition pattern ofthe short TTIs is also similarly changed in accordance with the lengthof the PDCCH.

FIG. 32 is an explanatory diagram illustrating a disposition example ofshort TTIs. FIG. 32 illustrates a disposition example of the short TTIsin a case in which the length of the PDCCH is 3 OFDM symbols, that is,the length of the PDSCH is 11 OFDM symbols. In the example illustratedin FIG. 32, the short TTIs are disposed intermittently by decimating thelevels of the short TTIs with level 1 at every other OFDM symbol.

FIG. 33 is an explanatory diagram illustrating a disposition example ofshort TTIs. FIG. 33 illustrates a disposition example of the short TTIsin a case in which the length of the PDCCH is 2 OFDM symbols, that is,the length of the PDSCH is 12 OFDM symbols. In the example illustratedin FIG. 33, the short TTIs are also disposed intermittently bydecimating the short TTIs with level 1 at every other OFDM symbol.

FIG. 34 is an explanatory diagram illustrating a disposition example ofshort TTIs. FIG. 34 illustrates a disposition example of the short TTIsin a case in which the length of the PDCCH is 1 OFDM symbol, that is,the length of, the PDSCH is 13 OFDM symbols. In the example illustratedin FIG. 34, the short TTIs are also disposed intermittently bydecimating the short TTIs with level 1 at every other OFDM symbol.

In a case in which the short TTIs are disposed intermittently bydecimating the levels of the short TTIs at every other OFDM symbol, forexample, as described with reference to FIG. 21, the base station 100notifies the terminal apparatus 200 of the disposition pattern of theshort TTIs and the information regarding the length of the PDCCH withPCFICH in advance, as in the operation example illustrated in FIG. 31.Even in a case in which the short TTIs are disposed by decimating thelevels of the short TTIs at every other OFDM symbol, the terminalapparatus 200 can know which disposition pattern of the short TTIs isused since the terminal apparatus 200 knows the information regardingthe length of the PDCCH. Then, the terminal apparatus 200 can performthe appropriate process of decoding the data of the short TTIs since theterminal apparatus 200 knows the disposition pattern of the short TTIsin advance.

(1.4.3. Third Operation Example)

Next, a third operation example of the base station 100 and the terminalapparatus 21 according to the embodiment of the present disclosure willbe described. As described above, in the case in which transmission andreception of data at the short transmission time interval are caused tocoexist with transmission and reception of data at the existingtransmission time interval, a technology for causing terminalapparatuses corresponding to transmission and reception of data at theshort transmission time interval to perform an effective process isnecessary. In the third operation example, an example of an operation inwhich the terminal apparatus corresponding to transmission and receptionof data at the short transmission time interval can perform an effectiveprocess from a different viewpoint from the first operation example willbe described.

For the short TTI, a purpose for controlling an application mounted onthe terminal apparatus 200 at a low latency from the base station 100 ora network in the back of the base station 100 is assumed. Accordingly,for the short TTI, the data arrives at each time from the Internet orthe like connected to the P-GW in the back of the network at a time atwhich a small amount of control data is necessary, unlike a method ofcaching data in an S-GW or the base station 100 and supplying the cached(buffered) data. When the small amount of control data does not arriveat the base station 100, the base station 100 does not know when thesmall amount of control data is transmitted from the base station 100 tothe terminal apparatus 200 in this situation. As the application mountedon the terminal apparatus 200, application software controlling a drone,application software controlling a vehicle, or the like can beexemplified. In this way, for the short TTI, a use case in which it isnecessary to send data at a low latency from the base station 100 to theterminal apparatus 200 although the data is a small amount of data canbe assumed. In the third embodiment, the scheduling technology necessaryto send data at a low latency from the base station 100 to the terminalapparatus 200 will be described. Herein, the scheduling indicates thatthe base station 100 notifies the terminal apparatus 200 of a locationof a downlink resource to be used by the terminal apparatus 200.

As a use case other than the application software controlling a drone orthe application software controlling a vehicle, for example,synchronization of a game can be exemplified. As network games, thereare many games in which it is necessary for a plurality of users tosynchronize their positions on a map via a network. FIG. 35 is anexplanatory diagram illustrating an example of a map displayed on theterminal apparatus 200 of each user performing a network game. FIG. 35illustrates an example of the map on which the positions of two usersare displayed. As illustrated in FIG. 35, synchronization of theposition of the users on the map is necessary in a game in which aplurality of users attack one other in the map of a common downtown.This is because when synchronization is not achieved, there is a case inwhich even when a user considers a partner to be in front of the eyes ofthe user on his or her terminal apparatus and attacks the partner, thepartner is actually moving in a distant place. It is necessary to updatean application in which synchronization of the positions of users on themap is necessary, at a low latency so that the mutual positions aresynchronized.

First, scheduling of a downlink of LTE of the related art will bedescribed. One resource block is formed by 12 subcarriers. An intervalof the subcarrier is 15 kHz. Accordingly, the width of the resourceblock in a frequency direction is 180 kHz. In a case in which thebandwidth is 20 MHz, 100 resource blocks can be disposed within 20 Hz.Here, when the 100 resource blocks are handled without change, thenumber of bits necessary for the scheduling may be 100 bits.Accordingly, a concept called a resource block group (RBG) in which 4resource blocks belong to one group will be introduced. When 4 resourceblocks are scheduled using one RGB as an RBG unit, the number of bitsnecessary for the scheduling can be reduced up to 25 bits. That is, aneNodeB notifies a UE of scheduling information formed by the 25-bitmapand indicating which RBG a certain UE uses among 25 RBGs. A first slotRBG and a second slot RBG are in 1 subframe but the same scheduling isperformed for both the RBGs. FIG. 36 is an explanatory diagramillustrating a first slot RGB and a second slot RGB which are in 1subframe. DCI in the PDCCH of subframe #0 includes 25-bit schedulinginformation. The 25-bit scheduling information designates RBG insubframe #0. The scheduling information is for one UE. In a case inwhich 25 bits are all 1, one UE uses all the resource blocks of subframe#0. Besides, for example, when the eNodeB designates“0001000000000010000000000” and the scheduling information, one UE canalso use resources at separate frequencies.

When a resource block (short PRB: short PHY resource block) of the shortTTI is introduced, a resolution in a time direction becomes fine. In ascheduling method of the related art, there is no resolution in the timedirection. In the related art, as described above, the resource blocksare grouped in the frequency direction and a bitmap of the schedulinginformation can be compressed as RBG. However, in a case in which theresolution in the time direction becomes fine as in the short TTIs,countermeasures may not be taken.

In a case in which first 3 OFDM symbols are used with the PDCCH among 14OFDM symbols in the time direction and the short TTIs are set to 1 OFDMsymbol, 11 short TTIs can be disposed in the time direction in thesubframe. When resources are designated in 25 RBGs with 25 bits in thefrequency direction and resources are designated with 11 bits in thetime direction, 25×11=275 bits, that is, bits of 11 multiples of 25 bitsof the related art, are necessary for minimum resources of the shortTTIs. It is not possible to include a total of 300 bits, 275 bits of theshort TTIs and 25 bits in the normal TTIs, in DCI of the PDCCH todesignate the resources of the short TTIs of one UE since the field ofthe PDCCH is limited.

Accordingly, a method of performing scheduling of the short TTIs byignoring a resolution in the time direction will be described. The basestation 100 designates RBGs for scheduling in the frequency directionusing the same bitmap as the related art. When the PDCCH occupies 3 OFDMsymbols in the case of the short TTIs with level 1 in which 1 OFDMsymbol is set as the TTI, the PDSCH is 11 OFDM symbols. Therefore, amaximum of 11 short TTIs are disposed in 1 subframe. Here, it is assumedthat 11 short TTIs disposed in 1 subframe are all allocated to the sameterminal apparatus 200. FIG. 37 is an explanatory diagram illustratingan allocation example of short TTIs to the terminal apparatus 200 and isan explanatory diagram illustrating a for in which 11 short TTIsdisposed in 1 subframe are all allocated to the same terminal apparatus200. By using the method of ignoring the resolution in the timedirection, it is possible to minimize an increase in the schedulinginformation when the short TTIs are introduced.

For the scheduling information to be added as information for the shortTTIs, it is necessary to distinguish whether a bitmap of the schedulinginformation is a bitmap for the short TTIs. Accordingly, it is necessaryto newly prepare the bitmap for the short TTI in addition to a bitmapfor the TTI of the related art.

In a case in which there are 25 RBGs at the bandwidth of 20 MHz, thebitmap of the scheduling information for the normal TTIs has 25 bits.The bitmap of the scheduling information for the short TTIs also has 25bits. That is, the bitmaps with a total of 50 bits are prepared for thenormal TTIs and the short TTIs. FIG. 38 is an explanatory diagramillustrating a form in which the normal TTIs and the short TTIs arescheduled in one terminal apparatus 200. In addition, Table 1 isexplanatory diagram illustrating examples of the bitmaps of thescheduling information for the normal TTIs and the short TTIs in thescheduling case as in FIG. 38. In the bitmaps, 0 means RBG not used forthe normal TTI or the short TTI and 1 means RBG used for the normal TTIand the short TTI.

TABLE 1 bitmap of scheduling information RBG index Bitmap of normal TTIBitmap of short TTI 0 0 1 1 0 0 2 1 0 3 1 0 4 0 0 5 0 0 6 0 0 7 0 0 8 00 9 0 0 10 0 0 11 0 0 12 0 0 13 0 0 14 0 0 15 0 0 16 0 0 17 0 0 18 0 019 0 0 20 0 0 21 0 0 22 0 0 23 0 0 24 0 0

In this way, when the resource kicks of the short TTIs are introducedand the resources are designated with 11 bits in the time direction, thescheduling information of a total of 300 bits is necessary. However, byignoring the resolution in the time direction by ignoring the resolutionin the time direction, it is possible to reduce the schedulinginformation up to a total of 50 bits.

FIG. 39 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according to the embodimentof the present disclosure. FIG. 39 illustrates an operation example ofthe base station 100 and the terminal apparatus 200 when the basestation 100 notifies the terminal apparatus 200 of the schedulinginformation for the short TTIs. Hereinafter, an operation example of thebase station 100 and the terminal apparatus 200 according to theembodiment of the present disclosure will be described with reference toFIG. 39.

The base station 100 notifies the terminal apparatus 200 of RBG for theshort TTIs in 25 RBGs with the bitmap in the semi-static manner (stepS301). For example, the notification unit 153 performs the process ofstep S301. When the base station 100 performs the notification with thebitmap in the semi-static manner, system information or dedicatedsignaling is used.

Subsequently, the base station 100 performs scheduling of RBG with thePDCCH (step S302). For example, the notification unit 153 performs theprocess of step S302.

The terminal apparatus 200 knows whether the scheduled RBG is for theshort TTIs or the normal TTIs, and then decodes data transmitted fromthe base station 100 (step S303). For example, the reception processingunit 243 performs the process of step S303.

Next, a method of further reducing the scheduling information of theshort TTIs will be described. For example, the base station 100 maynotify each terminal apparatus 200 of the short TTIs of RBG among 25RBGs one subframe using RRC signaling in advance. In addition, forexample, the base station 100 may designate that the RBG is normally forthe short TTIs in the system information broadcasted to the terminalapparatuses 200 rather than each terminal apparatus 200. In this way,when RBG for the short TTIs is designated in advance, 25-bit schedulinginformation added to designate the short TTIs is not necessary, and thusit is possible to reduce overhead of a control bit.

In the above-described method, the scheduling in the RBG unit, that is,the scheduling in the frequency direction, can be performed dynamically,that is, in a subframe unit. On the other band, scheduling at a shortTTI level in one subframe is not performed. Accordingly, when the PDCCHis assumed to occupy 3 OFDM symbols, the PDSCH is 11 OFDM symbols.Therefore, the method can be said to be a method for a case in which the11 OFDM symbols are all used by the same terminal apparatus 200.

On the other hand, for example, even when there is data only in thefirst OFDM symbol among 11 OFDM symbols and there is no data in theremaining OFDM symbols (null data is put), the terminal apparatus 200attempt to decode the short TTIs of all the OFDM symbols.

In a case in which there are 11 short TTIs in one subframe in the timedirection, data for the terminal apparatus 200 is put in the first twoshort TTIs, and the remaining 9 short TTIs are empty, it is wasteful forthe terminal apparatus 200 to decode the data of all the 11 short TTIs,and thus a power consumption amount of the terminal apparatus 200wastefully increases.

Accordingly, for example, in a case in which it is confirmed that it isnot necessary to decode the data of the short TTI after a certain OFDMsymbol, the base station 100 puts information indicating that this datais end data in the subframe, inside the data of the short TTI of theOFDM symbol. FIG. 40 is an explanatory diagram illustrating data ofshort TTIs put only in first 2 OFDM symbols among 11 OFDM symbols. Thebase station 100 puts information indicating that the data is end datain the subframe inside the data of the short TTI of the second OFDMsymbol. In this way, the terminal apparatus 200 may decode only the dataof the first 2 short TTIs. Then, the power consumption can be confinedto consumption necessary to decode the data of the short TTIs.

A method of effectively utilizing the remaining 9 OFDM symbols in a casein which the data of the short TTIs is put only in the first 2 OFDMsymbols among the 11 OFDM symbols, as illustrated in FIG. 40 will bedescribed.

FIG. 41 is an explanatory diagram illustrating an example of a case inwhich each of 3 terminal apparatuses 200 decodes data of short TTIs.FIG. 41 illustrates an example of a case in which the terminal apparatus200 denoted by a UE A decodes the data of the short TTIs in the firstand second OFDM symbols, the terminal apparatus 200 denoted by a UE Bdecodes the data of the short TTIs in the third to seventh OFDM symbols,and terminal apparatus 200 denoted by the UE B decodes the data of theshort TTIs in the eighth to eleventh OFDM symbols.

In this way, in a case in which each of the plurality of terminalapparatuses 200 decodes the data of the short TTIs in one subframe, thebase station 100 may include data designating a starting position andtransmit the data to each terminal apparatus 200. Referring to the datatransmitted from the base station 100, the UE A can know that the datadestined for the self-apparatus starts from the first OFDM symbol. Onthe other hand, referring to the data transmitted from the base station100, the UE B and the UE C can know that the data of the first OFDMsymbol is not data destined for the self-apparatuses, and therefore donot perform decoding.

Similarly, referring to the data transmitted from the base station 100,the UE B can know that the data destined for the self-apparatus startsfrom the third OFDM symbol. Referring to the data transmitted from thebase station 100, the UE C can know that the data destined for theself-apparatus starts from the eighth OFDM symbol. The base station 100notifies the terminal apparatuses 200 that information indicating anending position is directed to each terminal apparatus 200 as in themethod described with reference to FIG. 40.

In the example illustrated in FIG. 41, resources of three terminalapparatuses 200 are multiplexed in one RBG without overlapping. Asillustrated in FIG. 41, the resource is not wasteful at all bytransmitting the data toward the three terminal apparatuses 200. Then,only a resource continuing between the starting position and the endingposition is allocated to one terminal apparatus 200.

In the scheduling information necessary for DCI in the PDCCH, 25 bitsare necessary for scheduling of RBG or the short TTIs in addition to 25bits necessary for scheduling of designation of RBG of the normal TTIs,and 4 bits are necessary to indicate the beginning position of 11 shortTTIs in the time direction. Therefore, 25×4=100 bits are necessary inall the 25 RBGs. Accordingly, the scheduling information has a total of25 bits+25 bits+100 bits=150 bits.

A method of compressing the scheduling information will be described.The base station 100 can eliminate the waste of the resources and canreduce the wasteful decoding in the terminal apparatus 200 bydesignating the beginning position and the ending position for each RBG.However, the 100-bit scheduling information is therefore added to DCI.Since an increase in the scheduling information leads to an increase inoverhead caused due to the scheduling information, the schedulinginformation is preferably small.

For example, depending on a specification, the number of short TTIs tobe permitted is limited to a maximum of 3 short TTIs for each subframein one terminal apparatus 200. This limitation may be variable or may befixed as a system. By limiting the number of short TTIs in this way, theterminal apparatus 200 can assume that the number of short TTIs of 1rather than 0 is a maximum of 3 short TTIs among 25 bits of thescheduling information for the short TTIs. Then, since 4 bits×3=12 bitsmay be added to designate 11 short TTIs of RBG corresponding to the 3short TTIs, the scheduling information has a total of 25 bits+25 bits+12bits=62 bits. The 62-bit scheduling information is necessary forallocation of the scheduling addressed to one terminal apparatus 200 inDCI. Accordingly, since the number of bits can be considerably reducedfrom 150 bits described above, an advantageous effect contributing tothe reduction in the overhead in the terminal apparatus 200 can beexpected.

The data of the short TTIs is a small amount and is receivedintermittently by the terminal apparatus 200. Nevertheless, as describedabove, when the resources of the short TTIs in 1 subframe are allallocated to one terminal apparatus 200, the waste of the resourcesincreases. Accordingly, different short TTIs in 1 subframe arepreferably caused to be used by different terminal apparatuses 200.

Accordingly, after the base station 100 designates RBG in which thereare 11 short TTIs, as described above, the terminal apparatus 200decodes all the 11 short TTIs in a state in which the terminal apparatus200 does not know which short TTI is destined for the self-apparatusamong the 11 short TTIs. FIG. 42 is an explanatory diagram illustratingan example in which the terminal apparatus 200 decodes all the 11 shortTTIs. This decoding method is referred to as blind decoding. Normally,the blind decoding is performed when the UE decodes DCI of the PDCCH. Inthis operation example, even in a case in which the terminal apparatus200 decodes the short TTI, the blind decoding is applied.

FIG. 43 is an explanatory diagram illustrating a destination of shortTTIs and an example of a result of CRC check in a certain terminalapparatus 200. In the example illustrated in FIG. 43, in a certainterminal apparatus 200, the number of pieces of data of the short TTIdestined for the self-apparatus is 4 among 11 short TTIs. Therefore, aresult of CRC check of the data is OK. Since the number of pieces ofdata of the short TTIs destined for the other UEs is 7, a result of CRCcheck of the data is NG.

As illustrated in FIG. 43, the data destined for the self-apparatus andthe data destined for the other UEs can coexist in the data of the shortTTIs in one subframe (of course, there is also a possibility of the datadestined for the self-apparatus not existing). The base station 100performs CRC on the data with an ID (C-RNTI or the like) unique to theterminal apparatus 200. Accordingly, except that the terminal apparatus200 decodes the data destined for the self-apparatus, the result of CRCis not OK. Since the terminal apparatus 200 also decodes the data forother users (other terminal apparatuses 200), there are a portion onwhich CRC is an error and a portion on which CRC is not an error.However, the terminal apparatus 200 assumes that CRC is an error anddoes not respond to the base station 100 with NACK of data failure. Thisis because the data may be data of the other users (the other terminalapparatuses 200). When CRC is an error, the terminal apparatus 200 cantake a method of returning NACK among the following three methods.

(1) First Method

The first method is a method of not returning NACK at all. The terminalapparatus 200 does not return NACK at all even when CRC is an error. Inthis method, the base station 100 does not ascertain whether theterminal apparatus 200 has really received the data.

(2) Second Method

The second method is a method of not returning NACK when a result of CRCis OK even in one of the resources in the designated short TTIs andreturning NACK in a case in which the results of CRC are all NG. In thismethod, the terminal apparatus 200 does not return ACK or NACK for eachshort TTI. However, in this method, the base station 100 can partiallyknow whether the base station 100 can correctly transmit the data,compared to the first method.

(3) Third Method

The third method is a method of acquiring the number of pieces of datadestined for the self-apparatus among 11 pieces of data of the shortTTIs from the base station, for example, in a case in which there arethe 11 short TTIs, and returning ACK when a designated number is thesame as the number of OK results of CRC check and returning NACK when,the designated number is different from the number of OK results of CRCcheck. This method may not he used in a case in which the terminalapparatus 200 may not acquire the number of pieces of data destined forthe self apparatus among the 11 pieces of data of the short TTIs fromthe base station 100 in advance. However, when the terminal apparatus200 can acquire the number of pieces of data destined for theself-apparatus in a previous subframe in a DCI format in a subsequentsubframe from the base station 100, the terminal apparatus 200 canreturn ACK or NACK on the basis of information regarding the number ofpieces of data acquired from the base station 100.

In addition, when the base station 100 puts information indicating thatthe data destined for a certain terminal apparatus 200 ends here in asubframe and information regarding the number of pieces of datatransmitted toward the terminal apparatus 200 inside the subframe, theterminal apparatus 200 can know the number of pieces of data destinedfor the self apparatus in the subframe. FIG. 44 is an explanatorydiagram illustrating information transmitted toward the terminalapparatus 200 by the base station 100. FIG. 44 is an explanatory diagramillustrating an example in which the base station 100 puts informationindicating that the data destined for a certain terminal apparatus 200ends here in a subframe and information regarding the number of piecesof data transmitted toward the terminal apparatus 200 in the subframe.In the example illustrated in FIG. 44, for the data destined to thecertain terminal apparatus 200, the base station 100 puts theinformation indicating that the data of the ninth short TTI from thebeginning is the final in the data of the ninth short TTI front thebeginning. At this time, the base station 100 puts the fact that thedata of three short TTIs is transmitted to the terminal apparatus 200,in the data of the short TTI. The terminal apparatus 200 can know thatthe number of pieces of data destined for the self-apparatus is 3 in thesubframe by confirming the information. Accordingly, each terminalapparatus 200 responds to the base station 100 with ACK when the numberof OK results of the CRC check is 3, and responds to the base station100 with NACK when the number of OK results is not 3.

FIG. 45 is a flowchart illustrating an operation example of the basestation 100 and the terminal apparatus 200 according, to the embodimentof the present disclosure. FIG. 45 illustrates an operation example, ofthe base station 100 and the terminal apparatus 200 corresponding to theabove-described third method. Hereinafter an operation example of thebase station 100 and the terminal apparatus 200 according to theembodiment of the present disclosure will be described with reference toFIG. 45.

The base station 100 designates the resource in which the data of theshort TTI is put in the PDCCH of each subframe (step S311). For example,the notification unit 153 performs the process of step S311.

Subsequently, the base station 100 transmits the data destined for eachterminal apparatus 200 with the short TTIs. Then, information indicatingthat the data of the short TTI is the final here in each subframe amongthe final data of the short TTI destined for a certain terminalapparatus 200 in the subframe and the information regarding the numberof pieces of data transmitted toward the terminal apparatus 200 in thesubframe are notified of (step S312). For example, the notification unit153 performs the process of step S312.

The terminal apparatus 200 knows whether the scheduled RBG is for theshort TTIs or the normal TTIs, and then decodes the data. Then, theterminal apparatus 200 sequentially decodes the data of the short TTIsfrom the beginning when the scheduled RBG is for the short TTIs (stepS313). For example, the reception processing unit 243 performs theprocess of step S313.

Then, the terminal apparatus 200 responds to the base station 100 withACK or NACK on the basis of the information transmitted in the foregoingstep S312 from the base station 100 (step S314). For example, thenotification unit 245 performs the process of step S314. Each terminalapparatus 200 responds to the base station 100 with ACK when the numberof pieces of data of the short TTIs destined for the self-apparatus inthe subframe is the same as the number of OK results of the CRC on thebasis of the information transmitted in the foregoing step S312 from thebase station 100. The terminal apparatus 200 responds to the basestation 100 with NACK when the number of pieces of data of the shortTTIs is different from the number of OK results.

In the third method, the degree of freedom of the scheduling isconsiderably high since the base station 100 can designate the resourcescontinuously or at intervals in the frequency direction and the timedirection. In addition, the number of bits necessary for allocation ofthe, scheduling is small when the response of ACK/NACK of HARQ is notconsidered.

In addition, as in the above-described second method or third method, 4bits are necessary per RBG for the base station 100 to designate thenumber of pieces of effective data in the case of a method of comparingthe assumed number of pieces of effective data to the number of piecesof successfully received data. When a case in which 25 RBGs are occupiedby the short TTIs is assumed, information regarding 100 bits isnecessary for the base station 100 to designate the number of pieces ofeffective data. However, as described above, by limiting the number ofRBGs usable with the short TTIs per subframe, it is possible to reducethe number of bits for designating the number of pieces of effectivedata. For example, by limiting the number of RBGs usable with the shortTTIs per subframe to 3, it is possible to suppress the number of bitsfor designating the number of pieces of effective data to 12 bits.

As described above, in LTE of the related art, the eNodeB can allocate25 bits to the scheduling information in a case in which the bandwidthis 20 MHz. Accordingly, resources separated at frequency can beallocated to one UE. Even in the above-described three methods ofresponding with ACK or NACK, the base station 100 can freely allocate 25resources disposed in the frequency direction to each terminal apparatus200 in a similar way.

(1.4.4. Conclusion of Operation Examples)

The three operations examples of the base station 100 and the terminalapparatus 200 according to the embodiment of the present disclosure havebeen exemplified. Note that the base station 100 and the terminalapparatus 200 according to the embodiment of the present disclosure maynot independently operate the above-described three operation examples,but may operate a plurality of operation examples in combination. Inaddition, the base station 100 and the terminal apparatus 200 accordingto the embodiment of the present disclosure may combine only some of theabove-described operations when the base station 100 and the terminalapparatus 200 may combine the plurality of operation examples.

For example, the base station 100 and the terminal apparatus 200according to the embodiment of the present disclosure may combine anoperation of notifying of the resources to be used to transmit andreceive data in the short TTIs indicated in the first operation exampleand an operation at the time of preparation of the short TTIs withvarious levels.

<2. Application Examples>

The technique according to the present disclosure is applicable tovarious products. The base station 100 may also be implemented, forexample, as any type of evolved Node B (eNB) such as macro eNBs andsmall eNBs. Small eNBs may cover smaller cells than the macro cells ofpico eNBs, micro eNBs, home (femt) eNBs, or the like. Instead, the basestation 100 may be implemented as another type of base station such asNodes B, base transceiver stations (BTSs), or the like. The base station100 may include the main apparatus (which is also referred to as basestation apparatus) that controls wireless communication and one or moreremote radio beads (RRHs) that are disposed at different locations fromthat of the main apparatus. Also, various types of terminals describedbelow may function as the base station 100 by temporarily orsemi-permanently executing the functionality of the base station.

Further, for example, the terminal apparatus 200 may be implemented as amobile terminal such as smartphones, tablet personal computers (PCs),notebook PCs, portable game terminals, portable/dongle mobile routers,and digital cameras, or an in-vehicle terminal such as car navigationapparatuses. In addition, the terminal apparatus 200 may be implementedas a machine type communication (MTC) for establishing a machine tomachine communication (M2M). Furthermore, the terminal apparatus 200 maybe implemented as a wireless communication module (e.g. integratedcircuit module constituted with a single die) that is mounted on theseterminals.

<2.1. Application Examples for Base Station> (First Application Example)

FIG. 46 is, a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 and the base stationapparatus 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or a plurality of antennaelements (e.g. a plurality of antenna elements constituting a MIMOantenna) and is used for the base station apparatus 820 to transmit andreceive a wireless signal. The eNB 800 may include the plurality of theantennas 810 as illustrated in FIG. 46, and the plurality of antennas810 may, for example, correspond to a plurality of frequency bands usedby the eNB 800. It should be noted that while FIG. 46 illustrates anexample in which the eNB 800 includes the plurality of antennas 810, theeNB 800 may include the single antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a wireless communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of an upper layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data in asignal processed by the wireless communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may generate a bundled packet by bundling data from aplurality of base band processors to transfer the generated bundledpacket. In addition, the controller 821 may also have a logical functionof performing control such as radio resource control, radio bearercontrol, mobility management, admission control, and scheduling. Thecontrol may be performed in cooperation with a surrounding eNB or a corenetwork. In addition, the memory 822 includes a RAM and a ROM, andstores a program executed by the controller 821 and a variety of controldata (such as, for example, terminal list, transmission power data, andscheduling data).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to the core network 824. The controller821 may communicate with a core network node or another eNB via thenetwork interface 823. In this case, the eNB 800 may be connected to acore, network node or another eNB through a logical interface (e.g. S1interface or X2 interface). The network interface 823 may be a wiredcommunication interface or a wireless communication interface forwireless backhaul. When the network interface 823 is a wirelesscommunication interface, the network interface 823 may use a higherfrequency band for wireless communication than a frequency band used bythe wireless communication interface 825.

The wireless communication interface 825 supports a cellularcommunication system such as long term evolution (LTE) or LTE-Advanced,and provides wireless connection to a terminal located within the cellof the eN8 800 via the antenna 810. The wireless communication interface825 may typically include a base band (BB) processor 826, an RF circuit827, and the like. The BB processor 826 may, for example, performencoding/decoding, modulation/demodulation, multiplexing/demultiplexing,and the like, and performs a variety of signal processing on each layer(e.g. L1, medium access control (MAC), radio link control (RLC), andpacket data convergence protocol (PDCP)). The BB processor 826 may havepart or all of the logical functions as described above instead of thecontroller 821. The BB processor 826 may be a module including a memoryhaving a communication control program stored therein, a processor toexecute the program, and a related circuit, and the function of the BBprocessor 826 may be changeable by updating the program. In addition,the module may be a card or blade to be inserted into a slot of the basestation apparatus 820, or a chip mounted on the card or the blade.Meanwhile, the RF circuit 827 may include a mixer, a filter, anamplifier, and the like, and transmits and receives a wireless signalvia the antenna 810.

The wireless communication interface 825 may include a plurality of theBB processors 826 as illustrated in FIG. 46, and the plurality of BBprocessors 826 may, for example, correspond to a plurality of frequencybands used by the eNB 800. In addition, the wireless communicationinterface 825 may also include a plurality of the RF circuits 827, asillustrated in FIG. 46, and the plurality of RF circuits 827 may, forexample, correspond to a plurality of antenna elements. Note that, FIG.46 illustrates an example in which the wireless communication interface825 includes the plurality of BB processors 826 and the plurality of RFcircuits 827, but the wireless communication interface 825 may includethe single BB processor 826 or the single RF circuit 827.

In the eNB 800 illustrated in FIG. 46, one or more components includedin the processing unit 150 (the transmission processing unit 151 and/orthe notification unit 153) described above with reference to FIG. 7 maybe mounted in the wireless communication interface 825. Alternatively,at least some of the components may be mounted in the controller 821. Asan example, the eNB 800 may be equipped with a module including some orall components of the wireless communication interface 825 (for example,the BB processor 826) and/or the controller 821, and the above-describedone or more components may be mounted in the module. In this case, themodule may store a program causing the processor to function as theabove-described one or more components (that is, a program causing theprocessor to perform the operation of the above-described one or morecomponents) and execute the program. As another example, the programcausing the processor to function as the above-described one or morecomponents may be installed in the eNB 800, and the wirelesscommunication interface 825 (for example, the BB processor 826) and/orthe controller 821 may execute the program. As described above, the eNB800, the base station apparatus 820, or the module may be provided as anapparatus including the above-described one or more components, and theprogram causing the processor to function as the above-described one ormore components may be provided. In addition, a readable recordingmedium in which the program is recorded may be provided.

In addition, in the eNB 800 shown in FIG. 46, the wireless communicationunit 120 described with reference to FIG. 5 may be implemented by thewireless communication interface 825 (for example, the RF circuit 827).Moreover the antenna unit 110 may be implemented by the antenna 810. Inaddition, the network communication unit 130 may be implemented by thecontroller 821 and/or the network interface 823. In addition, thestorage unit 140 may be implemented by the memory 822.

(Second Application Example)

FIG. 47 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 830 includes one or more antennas 840,a base station apparatus 850, and an RRH 860. Each of the antennas 840and the RRH 860 may be connected to each other via an RF cable. Inaddition, the base station apparatus 850 and the RRH 860 may beconnected to each other by a high speed line such as optical fibercables.

Each of the antennas 840 includes a single or a plurality of antennaelements (e.g. plurality of antenna elements constituting a MIMOantenna), and is used for the RRH 860 to transmit and receive a wirelesssignal. The eNB 830 may include a plurality of the antennas 840 asillustrated in FIG. 47, and the plurality of antennas 840 may, forexample, correspond to a plurality of frequency bands used by the eNB830. Note that, FIG. 47 illustrates an example in which the eNB 830includes the plurality of antennas 840, but the eNB 830 may include thesingle antenna 840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a wireless communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are similar to the controller 821, the memory 822,and the network interface 823 described with reference to FIG. 46.

The wireless communication interface 855 supports a cellularcommunication system such as LTE and LTE-Advanced, and provides wirelessconnection to a terminal located in a sector corresponding to the RRH860 via the RRH 860 and the antenna 840. The wireless communicationinterface 855 may typically include a BB processor 856 and the like. TheBB processor 856 is similar to the BB processor 826 described withreference to FIG. 46 except that the BB processor 856 is connected to anRF circuit 864 of the RRH 860 via the connection interface 857. Thewireless communication interface 855 may include a plurality of the BBprocessors 856, as illustrated in FIG. 47, and the plurality of BBprocessors 856 may, for example, correspond to a plurality of frequencybands used by the eNB 830 respectively. Note that, FIG. 47 illustratesan example in which the wireless communication interface 855 includesthe plurality of BB processors 856, but the wireless communicationinterface 855 may include the single BB processor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (wireless communication interface 855) to the RRH860. The connection interface 857 may be a communication module forcommunication on the high speed line which connects the base stationapparatus 850 (wireless communication interface 855) to the RRH 860.

Further, the RRH 860 includes a connection interface 861 and a wirelesscommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(wireless communication interface 863) to the base station apparatus850. The connection interface 861 may be a communication module forcommunication on the high speed line.

The wireless communication interface 863 transmits and receives awireless signal via the antenna 840. The wireless communicationinterface 863 may typically include the RF circuit 864 and the like. TheRF circuit 864 may include a mixer, a filter, an amplifier and the like,and transmits and receives a wireless signal the antenna 840. Thewireless communication interface 863 may include a plurality of the RFcircuits 864 as illustrated in FIG. 47, and the plurality of RF circuits864 may, for example, correspond to a plurality of antenna elements.Note that, FIG. 47 illustrates an example in which the wirelesscommunication interface 863 includes the plurality of RF circuits 864,but the wireless communication interface 863 may include the single RFcircuit 864.

In the eNB 830 illustrated in FIG. 47, one components included in theprocessing unit 150 (the transmission processing unit 151 and/or thenotification unit 153) described above with reference to FIG. 5 may bemounted in the wireless communication interface 855 and/or the wirelesscommunication interface 863. Alternatively, at least some of thecomponents be mounted in the controller 851. As an example, the eNB 830may be equipped with a module including some or all components of thewireless communication interface 855 (for example, the BB processor 856)and/or the controller 851, and the above-described one or morecomponents may be mounted in the module. In this case, the module maystore a program causing the processor to function as the above-describedone or more components (that is, a program causing the processor performthe operation of the above-described one or more components) and executethe program. As another example, the program causing the processor tofunction as the above-described one or more components may be installedin the eNB 830, and the wireless communication interface 855 (forexample, the BB processor 856) and/or the controller 851 may execute theprogram. As described above, the eNB 830, the base station apparatus850, or the module may be provided as an apparatus including theabove-described one or more components, and the program causing theprocessor to function as the above-described one or more components maybe provided. In addition, a readable recording medium in which theprogram is recorded may be provided.

In addition, for example, in the eNB 830 shown in FIG. 47, the wirelesscommunication unit 120 described with reference to FIG. 5 may beimplemented by the wireless communication interface 863 (for example,the RF circuit 864). Moreover, the antenna unit 110 may be implementedby the antenna 840. In addition, the network communication unit 130 maybe implemented by the controller 851 and/or the network interface 853.In addition, the storage unit 140 may be implemented by the memory 852.

<2-2. Application Examples for Terminal Apparatus> (First ApplicationExample)

FIG. 48 is a block diagram illustrating an example, of a schematicconfiguration of a smartphone 900 to which the technology according tothe present disclosure may be applied. The smartphone 900 includes aprocessor 901, a memory 902, a storage 903, an external connectioninterface 904, a camera 906, a sensor 907, a microphone 908, an inputdevice 909, a display device 910, a speaker 911, a wirelesscommunication interface 912, one or more antenna switches 915, one ormore antennas 916, a bus 917, a battery 918, and a secondary controller919.

The processor 901 may be, for example, a CPU or a system on chip (SoC),and controls the functions of an application layer and other layers ofthe smartphone 900. The memory 902 includes a RAM and a ROM, and storesa program executed by the processor 901 and data. The storage 903 mayinclude a storage medium such as semiconductor memories and hard disks.The external connection interface 904 is an interface for connecting thesmartphone 900 to an externally attached device such as memory cards anduniversal serial bus (USB) devices.

The camera 906 includes an image sensor such as charge coupled devices(CCDs) and complementary metal oxide semiconductor (CMOS), and generatesa captured image. The sensor 907 may include a sensor group including,for example, a positioning sensor, a gyro sensor, a geomagnetic sensor,an acceleration sensor, and the like. The microphone 908 converts asound that is input into the smartphone 900 to an audio signal. Theinput device 909 includes, for example, a touch sensor which detectsthat a screen of the display device 910 is touched, a key pad, akeyboard, a button, a switch, or the like, and accepts an operation oran information input from a user. For example, the display device 910includes a screen such as liquid crystal displays (LCDs) and organiclight emitting diode (OLED) displays, and displays an output image ofthe smartphone 900. The speaker 911 converts the audio signal that isoutput from the smartphone 900 to a sound.

The wireless communication interface 912 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 912 may typicallyinclude the BB processor 913, the RF circuit 914, and the like. The BBprocessor 913 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 914 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 916. The wireless communicationinterface 912 may be a one-chip module in which the BB processor 913 andthe RF circuit 914 are integrated. The wireless communication interface912 may include a plurality of BB processors 913 and a plurality of RFcircuits 914 as illustrated in FIG. 48. Note that, FIG. 48 illustratesan example in which the wireless communication interface 912 includes aplurality of BB processors 913 and a plurality of RF circuits 914, butthe wireless communication interface 912 may include a single BBprocessor 913 or a single RF circuit 914.

Further, the wireless communication interface 912 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelesslocal area network (LAN) system in addition to the cellularcommunication system, and in this case, the wireless communicationinterface 912 may include the BB processor 913 and the RF circuit 914for each wireless communication system.

Each antenna switch 915 switches a connection destination of the antenna916 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 912.

Each of the antennas 916 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 912. The smartphone 900 may include aplurality of antennas 916 as illustrated in FIG. 48. Note that, FIG. 48illustrates an example in which the smartphone 900 includes a pluralityof antennas 916, but the smartphone 900 may include a single antenna916.

Further, the smartphone 900 may include the antenna 916 for eachwireless communication system. In this case, the antenna switch 915 maybe omitted from a configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 912, and the secondarycontroller 919 to each other. The battery 918 supplies electric power toeach block of the smartphone 900 illustrated in FIG. 48 via a feederline that is partially illustrated in the figure as a dashed line. Thesecondary controller 919, for example, operates a minimally necessaryfunction of the smartphone 900 in a sleep mode.

In the smartphone 900 illustrated m FIG. 48, one or more componentsincluded in the processing unit 240 (the acquisition unit 241 and/or thereception processing unit 243) described above with reference to FIG. 8may be mounted in the wireless communication interface 912,Alternatively, at least some of the components may be mounted in theprocessor 901 or the secondary controller 919. As an example, thesmartphone 900 may be equipped with a module including some or allcomponents of the wireless communication interface 912 (for example, theBB processor 913), the processor 901, and/or the secondary controller919, and the above-described one or more components may be mounted inthe module. In this case, the module may store a program causing theprocessor to function as the above-described one or more components(that is, a program causing the processor to perform the operation ofthe above-described one or more components) and execute the program. Asanother example the program causing the processor to function as theabove-described one or more components may be installed in thesmartphone 900, and the wireless communication interface 912 (forexample, the BB processor 913), the processor 901, and/or the secondarycontroller 919 may execute the program. As described above, thesmartphone 900 or the module may be provided as an apparatus includingthe above-described one or more components, and the program causing theprocessor to function as the above-described one or more components maybe provided. In addition, a readable recording medium in which theprogram is recorded may be provided.

In addition, for example, in the smartphone 900 shown in FIG. 48, thewireless communication unit 220 described with reference to FIG. 6 maybe implemented by the wireless communication interface 912 (for example,the RF circuit 914). Moreover, the antenna unit 210 may be implementedby the antenna 916. In addition, the storage unit 231 may be implementedby the memory 902.

(Second Application Example)

FIG. 49 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus 920 to which the technologyaccording to the present disclosure may be applied. The car navigationapparatus 920 includes a processor 921, a memory 922, a globalpositioning system (GPS) module 924, a sensor 925, a data interface 926,a content player 927, a storage medium interface 928, an input device929, a display device 930, a speaker 931, a wireless communicationinterface 933, one or more antenna switches 936, one or more antennas937, and a battery 938.

The processor 921 may be, for example, a CPU or a SoC, and controls thenavigation function and the other functions of the car navigationapparatus 920. The memory 922 includes a RAM and a ROM, and stores aprogram executed by the processor 921 and data.

The GPS module 924 uses a GPS signal received from a GPS satellite tomeasure the position (e.g. latitude, longitude, and altitude) of the carnavigation apparatus 920. The sensor 925 may include a sensor groupincluding, for example, a gyro sensor, a geomagnetic sensor, abarometric sensor, and the like. The data interface 926 is, for example,connected, to an in-vehicle network 941 via a terminal that is notillustrated, and acquires data such as vehicle speed data generated onthe vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g. CD or DVD) inserted into the storage medium interface 928. Theinput device 929 includes, for example, a touch sensor which detectsthat a screen of the display device 930 is touched, a button, a switch,or the like, and accepts operation or information input from a user. Thedisplay device 930 includes a screen such as LCDs and OLED displays, anddisplays an image of the navigation function or the reproduced content.The speaker 931 outputs a sound of the navigation function or thereproduced content.

The wireless communication interface 933 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 933 may typicallyinclude the BB processor 934, the RF circuit 935, and the like. The BBprocessor 934 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 935 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 937. The wireless communicationinterface 933 may be a one-chip module in which the BB processor 934 andthe RF circuit 935 are integrated. The wireless communication interface933 may include a plurality of BB processors 934 and a plurality of RFcircuits 935 as illustrated in FIG. 49. Note that, FIG. 49 illustratesan example in which the wireless communication interface 933 includes aplurality of BB processors 934 and a plurality of RF circuits 935, butthe wireless communication interface 933 may be a single BB processor934 or a single RE circuit 935.

Further, the wireless communication interface 933 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelessLAN system in addition to the cellular communication system, and in thiscase, the wireless communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each wireless communicationsystem.

Each antenna switch 936 switches a connection destination of the antenna937 among a plurality of circuits (for example, circuits, for differentwireless communication systems) included in the wireless communicationinterface 933.

Each of the antennas 937 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 933. The car navigation apparatus 920includes a plurality of antennas 937 as illustrated in FIG. 49. Notethat, FIG. 49 illustrates an example in which the car navigationapparatus 920 includes a plurality of antennas 937, but the carnavigation apparatus 920 may include a single antenna 937.

Further, the car navigation apparatus 920 may include the antenna 937for each wireless communication system. In this case, the antenna switch936 may be omitted from a configuration of the car navigation apparatus920.

The battery 950 supplies electric power to each block of the carnavigation apparatus 920 illustrated in FIG. 49 via a feeder line thatis partially illustrated in the figure as a dashed line, in addition,the battery 950 accumulates the electric power supplied from thevehicle.

In the car navigation apparatus 920 illustrated in FIG. 49, one or morecomponents included in the processing unit 240 (the acquisition unit 241and/or the reception processing unit 243) described above with referenceto FIG. 6 may be mounted in the wireless communication interface 933.Alternatively, at least some of the components may be mounted in theprocessor 921. As an example, the car navigation apparatus 920 may beequipped with a module including some or all components of the wirelesscommunication interface 933 (for example, the BB processor 934), and theabove-described one or more components may be mounted in the module. Inthis case, the module may store a program causing the processor tofunction as the above-described one or more components (that is, aprogram causing the processor to perform the operation of theabove-described one or more components) and execute the program. Asanother example, the program causing the processor to function as theabove-described one or more components may be installed in the carnavigation apparatus 920, and the wireless communication interlace 933(for example, the BB processor 934) and/or the processor 921 may executethe program. As described above, the car navigation apparatus 920 or themodule may be provided as an apparatus including the above-described oneor more components, and the program causing the processor to function asthe above-described one or mote components may be provided. In addition,a readable recording medium in which the program is recorded may beprovided.

In addition, for example, in the car navigation apparatus 920 shown inFIG. 49, the wireless communication unit 220 described with reference toFIG. 6 may be implemented by the wireless communication interface 933(for example, the RF circuit 935). Moreover, the antenna unit 210 may beimplemented by the antenna 937. In addition, the storage unit 230 may beimplemented by the memory 922.

In addition, the technology of the present disclosure may also berealized as an in-vehicle system (or a vehicle) 940 including one ormore blocks of the car navigation apparatus 920, the in-vehicle network941, and a vehicle module 942. In other words, the in-vehicle system (ora vehicle) 940 may be provided as a device which includes theacquisition unit 241 and/or the reception processing unit 243. Thevehicle module 942 generates vehicle data such as vehicle speed, enginespeed, and trouble information, and outputs the generated data to thein-vehicle network 941.

<3. Conclusion>

The embodiment of the present disclosure, as described above, providesthe base station 100 that notifies the terminal apparatuses of alocation where data is in resources at the short transmission timeinterval in the case in which transmission and reception of data at theshort transmission time interval are caused to coexist with transmissionand reception of data at the existing transmission time interval.

In addition, the embodiment of the present disclosure provides theterminal apparatus 200 which the base station 100 notifies of thelocation where the data is in the resources at the short transmissiontime interval in the case in which transmission and reception of data atthe short transmission time interval are caused to coexist withtransmission and reception of data at the existing transmission timeinterval.

The base station 100 according to the embodiment of the presentdisclosure notifies the terminal apparatus 200 of the location where thedata is in the resources at the short transmission time interval so thatthe terminal apparatus 200 can perform the efficient reception process,in the case in which transmission and reception of data at the shorttransmission time interval are caused to coexist with transmission andreception of data at the existing transmission time interval. Inaddition, the terminal apparatus 200 according to the embodiment of thepresent disclosure is notified of the location where the data is in theresources at the short transmission time interval by the base station100, in the case in which transmission and reception of data at theshort transmission time interval are caused to coexist with transmissionand reception of data at the existing transmission time interval, andthus the effective reception process can be performed.

According to the embodiment of the present disclosure, the base station100 can control an application mounted on the terminal apparatus 200 ina low latency and in a good response by notifying the terminal apparatus200 of the location where the data is in the resources at the shorttransmission time interval. In addition, according to the embodiment ofthe present disclosure, when the base station 100 notifies of thelocation of the data at the short transmission time interval, theterminal apparatus 200 can quickly return ACK or NACK to the basestation 100. Accordingly, according to the embodiment of the presentdisclosure, an improvement in throughput is prospected. In particular,according to the embodiment of the present disclosure, since the basestation 100 can effectively cause the resource of the short transmissiontime interval and the resource at the existing transmission timeinterval to coexist, the resources are not wasteful and an improvementin throughput can be expected.

The embodiment of the present disclosure provides the base station 100causes the terminal apparatus to be able to transmit and receive data inaccordance with an optimum length of the short transmission timeinterval in the terminal apparatus among a plurality of lengths of shorttransmission time interval at the time of transmission and reception ofdata at the short transmission time interval shorter than the existingtransmission time interval.

The embodiment of the present disclosure provides the terminal apparatus200 capable of transmitting and receiving data in accordance with anoptimum length of the short transmission time interval in the terminalapparatus among a plurality of lengths of short transmission timeinterval at the time of transmission and reception of data at the shorttransmission time interval shorter than the existing transmission timeinterval.

It may not be necessary to chronologically execute respective steps inthe processing, which is executed by each device of this specification,in the order described in the sequence diagrams or the flow charts. Forexample, the respective steps in the processing which is executed byeach device may be processed in the order different from the orderdescribed in the flow charts, and may also be processed in parallel.

Furthermore, it becomes possible to generate a computer program whichmakes a hardware device, such as a CPU, a ROM, and a RAM incorporated ineach device demonstrate the functions equivalent to the configurationsof the above described devices. In addition, it becomes also possible toprovide a storage medium which stores the computer program. In addition,respective functional blocks shown in the functional block diagrams maybe constituted from hardware devices or hardware circuits so that aseries of processes may be implemented by the hardware devices orhardware circuits.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art loom the description a this specification.

Additionally, the present technology may also be configured as below.

-   (1)

A wireless communication apparatus including:

a frame generation unit configured to generate a frame including aplurality of subframes;

a transmission unit configured to transmit the generated frame toanother communication apparatus; and

a notification unit configured to notify of information regarding aplurality of lengths of a short transmission time interval which is atransmission time interval shorter than one subframe period in thesubframe.

-   (2)

The wireless communication apparatus according to (1), furtherincluding:

a processing unit configured to select one length from the plurality oflengths on a basis of information regarding an ability of the othercommunication apparatus transmitted from the other communicationapparatus on a basis of the information regarding the plurality oflengths.

-   (3)

The wireless communication apparatus according to (2),

in which the processing unit transmits data, of the short transmissiontime interval using a part of a resource in a. short transmission timeinternal field in which data is transmitted at the short transmissiontime interval.

-   (4)

The wireless communication apparatus according to any one of (1) to (3),

in which the notification unit notifies of a correspondence relationbetween a length of each short transmission time interval, and a framenumber and a subframe number.

-   (5)

The wireless communication apparatus according to (2),

in which the processing unit includes data of the short transmissiontime interval with the plurality of lengths in one subframe.

-   (6)

The wireless communication apparatus according to (2),

in which the processing unit includes data of the short transmissiontime interval destined for a plurality of other communicationapparatuses in one subframe.

-   (7)

The wireless communication apparatus according to (2),

in which the processing unit intermittently disposes data of the shorttransmission time interval in one subframe.

-   (8)

The wireless communication apparatus according to (2),

in which the processing unit chances a length of a short transmissiontime interval field in which data is transmitted at the shorttransmission time interval in accordance with a length of a controlfield in the subframe.

-   (9)

The wireless communication apparatus according to an one of (1) to (8),

in which the notification unit notifies of a correspondence relationbetween the short transmission time interval and a subframe number in acase in which the short transmission time interval spans two subframes.

-   (10)

The wireless communication apparatus according to any one of (1) to (9),

in which setting of the plurality of lengths of the short transmissiontime interval differs for each cell.

-   (11)

A wireless communication apparatus including:

an acquisition unit configured to receive a frame including a pluralityof subframes and acquire information regarding a plurality of lengths ofa short transmission time interval which is a transmission time intervalshorter than one subframe period in the subframe from anothercommunication apparatus.

-   (12)

The wireless communication apparatus according to (11), furtherincluding:

a notification unit configured to notify the other communicationapparatus of information regarding an ability of the wirelesscommunication apparatus on a basis of the information regarding theplurality of lengths acquired by the acquisition unit.

-   (13)

The wireless communication apparatus according to (12),

in which the notification unit notifies of information regarding asoftware ability as the ability of the wireless communication apparatus.

-   (14)

The wireless communication apparatus according to (12) or (13),

in which the notification unit notifies of information regarding ahardware ability as the ability of the wireless communication apparatus.

-   (15)

The wireless communication apparatus according to any one of (11) to(14), in which the acquisition unit acquires data of the shorttransmission time interval of a length selected by the base station fromthe base station.

-   (16)

A wireless communication method including:

generating a frame including a plurality of subframes;

transmitting the generated frame to another communication apparatus; and

notifying of information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe.

-   (17)

A wireless communication method including:

receiving a frame including a plurality of subframes; and

acquiring information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe from a base station.

-   (18)

A computer program causing a computer to execute:

generating a frame including a plurality of subframes;

transmitting the generated frame to another communication apparatus; and

notifying of information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe.

-   (19)

A computer program causing a computer to execute:

receiving a frame including a plurality of subframes; and

acquiring information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe from a base station.

-   (20)

A wireless communication system including:

a first communication apparatus; and

a second communication apparatus,

in which the first communication apparatus includes

-   -   a frame generation unit configured to generate a frame including        a plurality of subframes,    -   a transmission unit configured to transmit the generated frame        to the second communication apparatus, and    -   a notification unit configured, to notify the second        communication apparatus of information regarding a plurality of        lengths of a short transmission time interval which is a        transmission time interval shorter than one subframe period in        the subframe, and

the second communication apparatus includes

-   -   an acquisition unit configured to receive the frame and acquire        information regarding the plurality of lengths of short        transmission interval in the subframe from the first        communication apparatus.

REFERENCE SIGNS LIST

-   1 system-   100 base station-   200 terminal apparatus

1. A wireless communication apparatus comprising: a frame generationunit configured to generate a frame including a plurality of subframes;a transmission unit configured to transmit the generated frame toanother communication apparatus; and a notification unit configured tonotify of information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe.
 2. The wireless communicationapparatus according to claim 1, further comprising: a processing unitconfigured to select one length from the plurality of lengths on a basisof information regarding an ability of the other communication apparatustransmitted from the other communication apparatus on a basis of theinformation regarding the plurality of lengths.
 3. The wirelesscommunication apparatus according to claim 2, wherein the processingunit transmits data of the short transmission time interval using a partof a resource in a short transmission time interval field in which datais transmitted at the short transmission time interval.
 4. The wirelesscommunication apparatus according to claim 1, wherein the notificationunit notifies of a correspondence relation between a length of eachshort transmission time interval, and a frame number and a subframenumber.
 5. The wireless communication apparatus according to claim 2,wherein the processing unit includes data of the short transmission timeinterval with the plurality of lengths in one subframe.
 6. The wirelesscommunication apparatus according to claim 2, wherein the processingunit includes data of the short transmission time interval destined fora plurality of other communication apparatuses in one subframe.
 7. Thewireless communication apparatus, according to claim 2, wherein theprocessing unit intermittently disposes data of the short transmissiontime interval in one subframe.
 8. The wireless communication apparatusaccording to claim 2, wherein the processing unit changes a length of ashort transmission time interval held in which data is transmitted atthe short transmission time interval in accordance with a length of acontrol field in the subframe.
 9. The wireless communication apparatusaccording to claim 1, wherein the notification unit notifies of acorrespondence relation between the short transmission time interval anda subframe number in a case in which the short transmission timeinterval spans two subframes.
 10. The wireless communication apparatusaccording to claim 1, wherein setting of the plurality of lengths of theshort transmission time interval differs for each cell.
 11. A wirelesscommunication apparatus comprising: an acquisition unit configured toreceive a frame including a plurality of subframes and acquireinformation regarding a plurality of lengths of a short transmissiontime interval which is a transmission time interval shorter than onesubframe period in the subframe from another communication apparatus.12. The wireless communication apparatus according to claim 11, furthercomprising: a notification unit configured to notify the othercommunication apparatus of information regarding an ability of thewireless communication apparatus on a basis of the information regardingthe plurality of lengths acquired by the acquisition unit.
 13. Thewireless communication apparatus according to claim 12, wherein thenotification unit notifies of information regarding a software abilityas the ability of the wireless communication apparatus.
 14. The wirelesscommunication apparatus, according to claim 12, wherein the notificationunit notifies of information regarding a hardware ability as the abilityof the wireless communication apparatus.
 15. The wireless communicationapparatus according to claim 11, wherein the acquisition unit acquiresdata of the short transmission time interval of a length selected by theother communication apparatus from the other communication apparatus.16. A wireless communication method comprising: generating a frameincluding a plurality of subframes; transmitting the generated frame toanother communication apparatus; and notifying of is regarding aplurality at lengths of a short transmission time interval which atransmission time in shorter than one subframe period in the subframe.17. A wireless communication method comprising: receiving a frameincluding a plurality of subframes; and acquiring information regardinga plurality of lengths of a short transmission time interval which is atransmission time interval shorter than one subframe period in thesubframe from a base station.
 18. A computer program causing a computerto execute: generating a frame including a plurality of subframes;transmitting the generated frame to another communication apparatus; andnotifying of information regarding a plurality of lengths of a shorttransmission time interval which is a transmission time interval shorterthan one subframe period in the subframe.
 19. A computer program causinga computer to execute: receiving a frame including a plurality ofsubframes; acquiring information regarding a plurality of lengths of ashort transmission time interval which is a transmission time intervalshorter than one subframe period in the subframe from a base station.20. A wireless communication system comprising: a first communicationapparatus; and a second communication apparatus, wherein the firstcommunication apparatus includes a frame generation unit configured togenerate a frame including a plurality of subframes, a transmission unitconfigured to transmit the generated frame to the second communicationapparatus, and a notification unit configured to notify the secondcommunication apparatus of information regarding a plurality of lengthsof a short transmission time interval which is a transmission timeinterval shorter than one subframe period in the subframe, and thesecond communication apparatus includes an acquisition unit configuredto receive the frame and acquire information regarding the plurality oflengths of the short transmission time interval in the subframe from thefirst communication apparatus.